NHA EKG Technician (CET) — All Questions

A technician measures the distance from the beginning of the P wave to the beginning of the QRS complex on a strip and counts four small boxes. What is the PR interval, and is it normal?

• a.0.04 second, which is shorter than normal
• b.0.16 second, which is normal✓
• c.0.08 second, which is normal
• d.0.40 second, which is longer than normal

Each small box equals 0.04 second at the standard paper speed of 25 mm/sec, so four small boxes equal 0.16 second. The normal PR interval is 0.12 to 0.20 second, so 0.16 second falls in range. The 0.04 and 0.08 answers miscount the boxes, and 0.40 second would require ten small boxes and would indicate a first-degree AV block.

What is the normal duration of the QRS complex in an adult?

• a.0.20 to 0.36 second
• b.Greater than 0.44 second
• c.0.12 to 0.20 second
• d.Less than 0.12 second✓

A normal QRS is under 0.12 second (fewer than three small boxes) because the ventricles depolarize rapidly through the bundle branches and Purkinje fibers. The 0.12 to 0.20 second range describes the PR interval, not the QRS. Values of 0.20 second or more suggest a bundle branch block or a beat that started in the ventricles, and 0.44 second is a QT-interval reference, not a QRS value.

Using the 300 method on a regular rhythm, a technician counts four large boxes between two consecutive R waves. What is the heart rate?

• a.150 beats per minute
• b.75 beats per minute✓
• c.100 beats per minute
• d.60 beats per minute

The 300 method divides 300 by the number of large boxes between R waves, so 300 divided by 4 equals 75 beats per minute. Sixty would require five large boxes, 100 would require three, and 150 would require two. The method only works when the rhythm is regular, because it assumes every R-R interval is the same.

A patient has an irregular rhythm. The technician counts 11 QRS complexes in a six-second strip. What is the approximate heart rate?

• a.11 beats per minute
• b.110 beats per minute✓
• c.66 beats per minute
• d.22 beats per minute

The six-second method multiplies the number of QRS complexes in six seconds by 10, giving 11 times 10, or about 110 beats per minute. This estimate is the preferred method for irregular rhythms because the 300 and 1500 methods assume equal R-R intervals. Multiplying by 2 or 6 instead of 10 gives the wrong scaling, since six seconds is one tenth of a minute.

What electrical event does the P wave represent on an EKG tracing?

• a.Atrial repolarization
• b.Atrial depolarization✓
• c.Ventricular depolarization
• d.Ventricular repolarization

The P wave is the small rounded deflection produced when the impulse from the SA node spreads across both atria and depolarizes them, which triggers atrial contraction. Ventricular depolarization produces the QRS complex, and ventricular repolarization produces the T wave. Atrial repolarization does occur, but it is buried inside the much larger QRS complex and is not normally visible.

A technician is explaining a tracing to a student and points to the rounded wave that follows each QRS complex. What does this wave represent?

• a.Depolarization of the ventricles
• b.Conduction delay at the AV node
• c.Repolarization of the ventricles✓
• d.Contraction of the atria

The T wave follows the QRS and represents ventricular repolarization, the recovery phase in which the ventricular cells return to their resting electrical state. Ventricular depolarization is the QRS itself. The AV node delay is represented by the flat segment within the PR interval, and atrial contraction follows the P wave.

Using the 1500 method, a technician counts 20 small boxes between two consecutive R waves on a regular strip. What is the heart rate?

• a.50 beats per minute
• b.75 beats per minute✓
• c.300 beats per minute
• d.100 beats per minute

The 1500 method divides 1500 by the number of small boxes between R waves: 1500 divided by 20 equals 75 beats per minute. The number 1500 is used because there are 1500 small boxes in one minute at 25 mm/sec. This method is the most precise of the calculation methods, but like the 300 method it requires a regular rhythm.

Which set of findings meets the criteria for normal sinus rhythm?

• a.Rate 80, irregularly irregular, no P waves, QRS 0.08 second
• b.Rate 80, regular, upright P before each QRS, PR 0.16, QRS 0.08 second✓
• c.Rate 112, regular, upright P before each QRS, PR 0.16, QRS 0.08 second
• d.Rate 52, regular, inverted P after each QRS, PR not measurable

Normal sinus rhythm requires a rate of 60 to 100, a regular rhythm, one upright P wave in front of every QRS, a PR interval of 0.12 to 0.20 second, and a QRS under 0.12 second. The choice at 112 meets every one of those criteria except the rate, which makes it sinus tachycardia rather than normal sinus rhythm. Absent P waves with an irregularly irregular ventricular response describes atrial fibrillation. A rate of 52 with P waves inverted after the QRS points to a junctional rhythm, in which the impulse starts below the atria and travels backward through them.

A sleeping athlete on telemetry shows a regular rhythm at 52 beats per minute with an upright P wave before each narrow QRS and a PR interval of 0.16 second. How should this rhythm be identified?

• a.Normal sinus rhythm
• b.Sinus bradycardia✓
• c.Junctional escape rhythm
• d.Second-degree AV block

Every measurement is normal except the rate, which is below 60, so the rhythm is sinus bradycardia. Normal sinus rhythm requires a rate of at least 60. A junctional escape rhythm would show absent or inverted P waves, and a second-degree AV block would show P waves that are not all followed by a QRS complex.

A patient with a fever of 103 degrees Fahrenheit has a regular rhythm at 124 beats per minute with an upright P wave before every narrow QRS. What is this rhythm?

• a.Sinus tachycardia✓
• b.Ventricular tachycardia
• c.Atrial flutter
• d.Supraventricular tachycardia

Sinus tachycardia is a sinus rhythm faster than 100 beats per minute, and it is a normal response to fever, pain, exercise, anxiety, or dehydration. Supraventricular tachycardia is usually faster than 150 and the P waves are hidden. Atrial flutter shows sawtooth flutter waves, and ventricular tachycardia produces wide QRS complexes with no P waves.

A pediatric strip shows upright P waves before every narrow QRS, a PR interval of 0.14 second, and R-R intervals that shorten with inhalation and lengthen with exhalation. What is this rhythm?

• a.Wandering atrial pacemaker
• b.Sinus arrhythmia✓
• c.Second-degree AV block, Mobitz I
• d.Atrial fibrillation

Sinus arrhythmia is a sinus rhythm whose only abnormality is an irregularity that varies with the breathing cycle, and it is a normal finding in children and young adults. Atrial fibrillation would have no identifiable P waves and an irregularly irregular rhythm. Wandering atrial pacemaker shows at least three different P wave shapes, and Mobitz I shows progressively lengthening PR intervals with a dropped QRS.

A strip shows no identifiable P waves, a wavy chaotic baseline, narrow QRS complexes, and R-R intervals that vary from beat to beat with no pattern. What is this rhythm?

• a.Atrial flutter
• b.Ventricular fibrillation
• c.Sinus arrhythmia
• d.Atrial fibrillation✓

Atrial fibrillation is described as irregularly irregular with no discernible P waves and a fibrillatory baseline, while the QRS stays narrow because conduction below the AV node is normal. Sinus arrhythmia still has clear P waves. Atrial flutter has organized sawtooth waves, and ventricular fibrillation has no QRS complexes at all.

A monitor strip shows a sawtooth baseline with regular atrial waves at about 300 per minute and a QRS after every fourth sawtooth wave. What is this rhythm?

• a.Atrial flutter with 4:1 conduction✓
• b.Coarse atrial fibrillation
• c.Sinus tachycardia with artifact
• d.Second-degree AV block, 4:1

Atrial flutter produces uniform sawtooth flutter waves, classically at 250 to 350 per minute, and the AV node blocks most of them so only every second, third, or fourth impulse reaches the ventricles. That physiologic filtering is normal protection and is not called second-degree AV block, which is a conduction defect occurring at ordinary atrial rates. Coarse atrial fibrillation has a chaotic, constantly changing baseline instead of identical repeating waves, and sinus tachycardia shows discrete P waves that stop at the QRS rather than marching straight through it.

An otherwise regular sinus strip contains one early beat with a P wave shaped differently from the others, followed by a normal narrow QRS and then a pause. What is the early beat?

• a.Escape beat
• b.Premature atrial contraction✓
• c.Premature ventricular contraction
• d.Premature junctional contraction

A premature atrial contraction arrives early and comes from an irritable site in the atria, so its P wave looks different from the sinus P waves but the QRS remains narrow because conduction to the ventricles is normal. A premature ventricular contraction would be wide and bizarre with no P wave. A junctional premature beat has an inverted or absent P wave, and an escape beat arrives late rather than early.

A patient reports sudden palpitations. The strip shows a perfectly regular narrow-complex rhythm at 180 beats per minute with P waves that cannot be identified. What is the most likely rhythm?

• a.Accelerated junctional rhythm
• b.Ventricular tachycardia
• c.Supraventricular tachycardia✓
• d.Sinus tachycardia

Supraventricular tachycardia is a regular narrow-complex rhythm, usually 150 to 250 beats per minute, in which the P waves are buried in the preceding T waves and cannot be seen. Sinus tachycardia usually stays under 160 and has visible P waves that speed up gradually. Ventricular tachycardia has wide QRS complexes, and an accelerated junctional rhythm runs about 60 to 100.

A strip shows a regular rhythm at 45 beats per minute with narrow QRS complexes and inverted P waves appearing immediately after each QRS. What is this rhythm?

• a.Junctional escape rhythm✓
• b.Idioventricular rhythm
• c.First-degree AV block
• d.Sinus bradycardia

When the junction takes over as pacemaker, the atria depolarize backward, so the P wave is inverted and may fall before, during, or after the QRS; at 40 to 60 beats per minute this is a junctional escape rhythm. Sinus bradycardia has upright P waves before the QRS. An idioventricular rhythm has wide QRS complexes at 20 to 40, and first-degree AV block has upright P waves with a long PR interval.

What is the inherent rate range of the AV junction when it functions as the heart's pacemaker?

• a.40 to 60 beats per minute✓
• b.20 to 40 beats per minute
• c.60 to 100 beats per minute
• d.100 to 150 beats per minute

The AV junction fires at an inherent rate of 40 to 60 beats per minute and takes over when the SA node fails or slows. The SA node is the primary pacemaker at 60 to 100, and the ventricular Purkinje network is the last-resort pacemaker at 20 to 40. A junctional rhythm faster than 60 is called accelerated junctional, and above 100 it is junctional tachycardia.

A sinus rhythm strip contains a single early beat that is wide and bizarre, has no preceding P wave, and has a T wave that points opposite to the QRS. What is the beat?

• a.Somatic tremor artifact in one lead
• b.Premature ventricular contraction✓
• c.Ventricular paced beat with capture
• d.Premature atrial contraction with aberrancy

A premature ventricular contraction originates below the bundle of His, so the impulse spreads muscle cell to muscle cell rather than through the fast conduction system, producing a wide bizarre QRS with no preceding P wave and a T wave that points opposite the QRS. A premature atrial contraction conducted with aberrancy is the genuinely competing answer: it is also early and wide, but it is preceded by its own early P wave, which this beat lacks. A paced beat carries a sharp pacing spike immediately in front of it, and tremor artifact rides on top of the baseline without replacing a beat or resetting the cycle.

A monitor alarms and the strip shows a regular wide-complex rhythm at 170 beats per minute with no visible P waves. The patient is unresponsive. What rhythm is displayed?

• a.Supraventricular tachycardia
• b.Sinus tachycardia with a bundle branch block
• c.Ventricular tachycardia✓
• d.Atrial flutter

Ventricular tachycardia is three or more consecutive PVCs at a rate above 100, appearing as a regular run of wide, uniform complexes without P waves, and it is a lethal rhythm when the patient has no pulse. Supraventricular tachycardia is narrow. Atrial flutter shows sawtooth waves, and while a rate-related bundle branch block can widen a sinus tachycardia, an unresponsive patient with this tracing must be treated as ventricular tachycardia and help summoned at once.

A telemetry strip suddenly shows chaotic, irregular waves of varying height with no identifiable P waves, QRS complexes, or T waves. What should the technician do first?

• a.Reposition the electrodes and print a new strip
• b.Immediately check the patient and call for emergency help✓
• c.Ask the patient to lie still and stop talking
• d.Chart the finding and continue monitoring

That description is ventricular fibrillation, a lethal rhythm in which the ventricles quiver and produce no cardiac output, so the technician must verify the patient at the bedside and activate the emergency response without delay. Documenting and waiting wastes the minutes that determine survival. Repositioning electrodes or asking the patient to hold still is the response to suspected artifact, and artifact is ruled out the moment the patient is found unresponsive and pulseless.

A monitor shows a nearly flat line with no waveforms in two different leads and the patient is unresponsive with no pulse. What is this rhythm?

• a.Loose lead artifact
• b.Ventricular fibrillation
• c.Idioventricular rhythm
• d.Asystole✓

Asystole is the absence of all electrical activity, appearing as a flat or nearly flat line, and it must be confirmed in more than one lead before it is accepted as true. Ventricular fibrillation still shows chaotic deflections, and an idioventricular rhythm shows wide slow complexes. A loose lead can mimic a flat line, which is exactly why the finding is confirmed in a second lead and at the bedside.

A strip shows wide QRS complexes at a regular rate of 32 beats per minute with no P waves. What is this rhythm called?

• a.Agonal artifact
• b.Junctional escape rhythm
• c.Idioventricular rhythm✓
• d.Sinus bradycardia

When the ventricles become the pacemaker of last resort, they fire at their inherent rate of 20 to 40 beats per minute and produce wide complexes without P waves, which is an idioventricular rhythm. A junctional escape rhythm runs 40 to 60 with narrow complexes. Sinus bradycardia has upright P waves and narrow QRS complexes, and this tracing is an organized rhythm rather than artifact.

A regular strip at 68 beats per minute has one upright P wave before every narrow QRS, and every PR interval measures 0.28 second. What is this rhythm?

• a.Normal sinus rhythm at a rate of 68
• b.Second-degree AV block, Mobitz type II
• c.Third-degree AV block with a junctional escape
• d.Sinus rhythm with a first-degree AV block✓

A PR interval that is constant but longer than 0.20 second defines first-degree AV block, in which every impulse still reaches the ventricles but is delayed. Normal sinus rhythm requires a PR of 0.12 to 0.20 second, so 0.28 second rules it out. Mobitz II drops beats without lengthening the PR, and this strip drops nothing. In third-degree block with a junctional escape, the P waves and QRS complexes march at independent rates, so no PR interval would measure the same value twice, let alone every time.

A strip shows PR intervals of 0.18, 0.24, 0.32 second, then a P wave with no QRS after it, and the pattern repeats. What is this rhythm?

• a.First-degree AV block with a sinus pause
• b.Second-degree AV block, Mobitz type II
• c.Second-degree AV block, Mobitz I (Wenckebach)✓
• d.Third-degree AV block with variable PR intervals

Mobitz I, also called Wenckebach, shows the PR interval getting progressively longer until one P wave is not conducted and a QRS is dropped, after which the cycle starts over. Mobitz II also drops beats, but the conducted PR intervals stay constant, which is the single feature that separates the two here. First-degree block never drops a beat at all, so pairing it with a pause misreads the dropped QRS as a sinus problem. In third-degree block the PR intervals vary randomly because the atria and ventricles are unrelated, rather than lengthening in an orderly sequence.

A strip shows a constant PR interval of 0.20 second on conducted beats, but every third P wave is suddenly not followed by a QRS complex. What is this rhythm?

• a.Premature atrial contractions that are not conducted
• b.Second-degree AV block, Mobitz II✓
• c.Second-degree AV block, Mobitz I
• d.Sinus arrhythmia

Mobitz II is identified by dropped QRS complexes with no warning and PR intervals that remain constant on the beats that do conduct. Mobitz I would show the PR lengthening before the drop. Sinus arrhythmia never drops a QRS, and non-conducted premature atrial contractions arrive early with abnormal P waves rather than on schedule.

A strip shows a regular ventricular rhythm at 40 beats per minute with wide QRS complexes, regular P waves at 80 per minute, and no consistent relationship between the P waves and the QRS complexes. What is this rhythm?

• a.Sinus bradycardia with premature atrial contractions
• b.Second-degree AV block, Mobitz I
• c.Junctional escape rhythm
• d.Third-degree (complete) AV block✓

In third-degree AV block nothing crosses the AV node, so the atria and ventricles beat independently: the P-P interval is regular, the R-R interval is regular, and the PR interval constantly changes. Mobitz I still conducts most beats with a lengthening PR. Sinus bradycardia keeps one P wave tied to each QRS, and a pure junctional escape rhythm would not show a separate faster atrial rate marching through the tracing.

A strip shows a sharp, narrow vertical spike immediately before each wide QRS complex at a regular rate of 70. What does this indicate?

• a.Sixty-cycle AC interference
• b.A ventricular paced rhythm✓
• c.Somatic tremor artifact
• d.A premature ventricular contraction pattern

A pacemaker spike is a thin vertical line marking the electrical impulse delivered by the device; a spike followed by a wide QRS indicates ventricular capture. AC interference appears as a uniform fuzzy band across the whole tracing rather than a single spike per beat. Premature ventricular contractions occur early and irregularly without spikes, and somatic tremor causes erratic jagged baseline movement.

A monitor alarms for ventricular fibrillation, but the technician finds the patient sitting up, alert, and brushing her teeth, and a regular narrow-complex rhythm is visible between the chaotic sections. What is the most likely explanation?

• a.Pacemaker malfunction
• b.Intermittent true ventricular fibrillation
• c.Third-degree AV block
• d.Muscle movement artifact✓

An alert, talking patient cannot be in ventricular fibrillation, and the presence of underlying normal complexes marching through the chaos identifies the tracing as motion artifact. True ventricular fibrillation has no organized QRS complexes anywhere and produces immediate unresponsiveness. AV block and pacemaker failure both produce organized, measurable patterns rather than chaotic noise tied to the patient's activity.

Which group of rhythms is considered immediately life-threatening and requires the technician to summon help right away?

• a.Sinus bradycardia, sinus tachycardia, and sinus arrhythmia
• b.First-degree AV block, atrial flutter, and premature atrial contractions
• c.Junctional rhythm, wandering atrial pacemaker, and paced rhythm
• d.Ventricular fibrillation, pulseless ventricular tachycardia, and asystole✓

Ventricular fibrillation, pulseless ventricular tachycardia, and asystole produce no effective cardiac output, so survival depends on immediate recognition and activation of the emergency response. The sinus rhythms in the first choice are common and often benign. First-degree block, flutter, and premature atrial beats need reporting but not emergency action, and junctional or paced rhythms usually maintain perfusion.

What does the QT interval measure on an EKG tracing?

• a.The delay of the impulse at the AV node
• b.The time between two consecutive R waves
• c.Atrial depolarization plus repolarization
• d.Ventricular depolarization plus repolarization✓

The QT interval is measured from the start of the QRS complex to the end of the T wave and represents the full cycle of ventricular depolarization and recovery; it normally occupies less than half of the R-R interval and generally measures under about 0.44 second at normal rates. Atrial depolarization is the P wave, and atrial repolarization is buried inside the QRS and is not measured. The AV nodal delay lies inside the PR interval, and the R-R interval measures rate and regularity.

A strip shows a normal sinus beat followed by a wide bizarre beat, then another sinus beat followed by another wide bizarre beat, repeating throughout the strip. What is this pattern called?

• a.Ventricular bigeminy✓
• b.Ventricular tachycardia
• c.Ventricular trigeminy
• d.A couplet

Bigeminy means every other beat is a premature ventricular contraction, alternating one normal beat and one PVC. Trigeminy is a PVC every third beat. A couplet is two PVCs in a row, and three or more consecutive PVCs at a rate above 100 constitute ventricular tachycardia.

Which premature ventricular contraction pattern is considered most dangerous because it can trigger ventricular tachycardia or fibrillation?

• a.An interpolated PVC between two normal beats
• b.A unifocal PVC that is late in the cycle
• c.A PVC followed by a full compensatory pause
• d.A PVC that lands on the T wave of the preceding beat✓

A PVC falling on the T wave, called the R-on-T phenomenon, arrives during the vulnerable relative refractory period of repolarization and can precipitate ventricular tachycardia or fibrillation. Unifocal PVCs that arrive later in the cycle are the least worrisome type. An interpolated PVC does not disturb the underlying rhythm, and a compensatory pause is a normal feature of most PVCs rather than a warning sign.

An otherwise normal sinus strip contains one early narrow beat with an inverted P wave right in front of it and a PR interval of 0.08 second. What is this beat?

• a.Premature atrial contraction
• b.Premature ventricular contraction
• c.Sinus escape beat
• d.Premature junctional contraction✓

A premature junctional contraction comes from the AV junction, so the atria depolarize retrograde and produce an inverted P wave with a short PR of less than 0.12 second, while the QRS stays narrow. A premature atrial contraction has an upright though differently shaped P wave with a normal PR. A PVC is wide with no P wave, and an escape beat comes late, not early.

What is the correct way to determine whether a ventricular rhythm is regular?

• a.March out the R-to-R intervals and check that they stay equal✓
• b.Compare the height of each R wave from one beat to the next
• c.March out the P-to-P intervals, since the atria govern the rate
• d.Check that every PR interval measures less than 0.20 second

Ventricular regularity is judged by marching out the R-to-R intervals with calipers or a paper edge and checking whether they stay the same. Marching out P-to-P intervals is a real measurement, but it reports ATRIAL regularity, and the two differ whenever conduction fails: in complete heart block the P-to-P intervals can be perfectly regular while the ventricles are not. R wave height reflects voltage and lead placement rather than timing, and measuring PR intervals evaluates AV conduction.

On standard EKG paper running at 25 mm/sec, how far apart are the vertical time markers printed at the top of the strip used for the six-second method?

• a.One second apart, so six intervals equal six seconds
• b.Six seconds apart, so one interval equals six seconds
• c.Half a second apart, so twelve intervals equal six seconds
• d.Three seconds apart, so two intervals equal six seconds✓

EKG paper is marked at three-second intervals, which equals 15 large boxes, so a six-second strip spans two marked intervals or 30 large boxes. Each large box is 0.20 second and each small box is 0.04 second at the standard 25 mm/sec speed. The other spacings do not correspond to how standard EKG paper is printed.

Where is the V1 electrode placed for a 12-lead EKG?

• a.Fifth intercostal space, right sternal border
• b.Fourth intercostal space, right sternal border✓
• c.Fifth intercostal space, left midclavicular line
• d.Fourth intercostal space, left sternal border

V1 sits in the fourth intercostal space at the right sternal border, and it is located by walking down from the sternal angle to the second rib, then counting the second, third, and fourth spaces. The fourth space at the left sternal border is V2. The fifth space at the left midclavicular line is V4, and there is no standard chest lead at the fifth space on the right sternal border.

A technician has correctly placed V1. Where does the V2 electrode go?

• a.Fifth intercostal space, left anterior axillary line
• b.Fourth intercostal space, left sternal border✓
• c.Directly below V1 in the fifth intercostal space
• d.Midway between V1 and V4

V2 is placed in the fourth intercostal space at the left sternal border, directly across the sternum from V1. The electrode placed midway between V2 and V4 is V3, and V3 is always positioned after V4 is located. The fifth space at the left anterior axillary line is V5.

Which chest electrode is placed in the fifth intercostal space at the left midclavicular line?

• a.V4✓
• b.V3
• c.V5
• d.V6

V4 is placed in the fifth intercostal space at the left midclavicular line, and it is located before V3 because V3 is defined as the midpoint between V2 and V4. V5 goes at the left anterior axillary line and V6 at the left midaxillary line, both level with V4 rather than following the rib spaces.

After placing V1, V2, and V4, where should the technician place V3?

• a.Midway between V2 and V4 on a straight line✓
• b.At the left anterior axillary line level with V4
• c.Directly below V2 in the fifth intercostal space
• d.Midway between V1 and V2 at the same level

V3 sits on a straight line halfway between V2 and V4, which is exactly why V4 is placed before V3 rather than in numerical order. Halfway between V1 and V2 would land on the sternum, over bone rather than over the heart. Dropping straight down from V2 ignores the diagonal that the chest wall follows as it curves toward the axilla, and the left anterior axillary line at the level of V4 is the position for V5.

A technician is placing V5 on a 12-lead EKG. Which description is correct?

• a.Fifth intercostal space, left midaxillary line
• b.Fourth intercostal space, left anterior axillary line
• c.Left anterior axillary line, on the same horizontal level as V4✓
• d.Sixth intercostal space, left anterior axillary line

V5 is placed at the left anterior axillary line on the same horizontal plane as V4 rather than by counting rib spaces, because the chest wall curves and the horizontal alignment keeps V4, V5, and V6 comparable. The midaxillary line at that level is V6. Counting to the sixth space or the fourth space would place the electrode too low or too high.

Where is the V6 electrode placed?

• a.Right midaxillary line, level with V4
• b.Left midaxillary line, level with V4 and V5✓
• c.Posterior axillary line, level with V4
• d.Left midclavicular line, sixth space

V6 is placed at the left midaxillary line on the same horizontal plane as V4 and V5, completing the left lateral view of the heart. The posterior axillary line is one space further back and is used for the additional posterior lead V7, not for V6. The right midaxillary line looks at the heart from the wrong side of the chest, and dropping to the sixth space at the midclavicular line abandons the horizontal plane that V4, V5, and V6 share.

Where should the limb electrodes be placed for a standard 12-lead EKG?

• a.On fleshy, non-muscular areas of the arms and lower legs, positioned symmetrically✓
• b.On the bony prominences of the wrists and ankles for the best signal
• c.On the upper chest and abdomen for all four limb leads
• d.Anywhere convenient, since limb lead position does not affect the tracing

Limb electrodes belong on flat, fleshy areas of the arms and lower legs, placed symmetrically on the right and left, because bone conducts poorly and muscle bellies generate tremor artifact. Torso placement is acceptable only for continuous monitoring or when a limb is missing, and it must be documented because it alters the tracing. Limb position does affect amplitude and axis, so it is never arbitrary.

A 12-lead tracing shows an inverted P wave, inverted QRS, and inverted T wave in lead I, while the chest leads look normal. What is the most likely cause?

• a.The left arm and left leg electrodes are reversed
• b.The V1 and V2 chest electrodes are reversed
• c.The right arm and left arm electrodes are reversed✓
• d.The right leg ground electrode is loose

Reversing the right and left arm electrodes flips the polarity of lead I, producing a globally negative complex in that lead while the chest leads, which do not depend on arm placement, remain normal. Swapping the left arm and left leg electrodes is the closest competitor and does disturb the frontal-plane leads, but it exchanges leads I and II and inverts lead III, so lead I still records an upright complex. Reversing V1 and V2 distorts only those two chest leads, and a loose right leg ground electrode produces baseline wander or noise rather than inversion.

A tracing shows a uniform, thick, fuzzy baseline with small spikes occurring exactly 60 times per second across all leads. What is the most likely cause?

• a.AC interference from nearby powered equipment✓
• b.Deep respiration moving the chest wall electrodes
• c.Electrodes that have dried out and lost contact
• d.A resting tremor of the patient's hands

Sixty-cycle interference is alternating current picked up from nearby electrical devices, cords, or fluorescent lights, and it produces a perfectly regular fuzzy band at exactly 60 hertz in every affected lead. The giveaway is the word exactly: no physiologic source repeats at a fixed 60 per second. A resting tremor produces irregular jagged spikes at a slower and varying rate, deep respiration causes a slow rolling baseline rather than fine spikes, and dried electrodes produce erratic noise or a flat trace confined to the leads they belong to.

An anxious, cold patient produces a tracing with irregular jagged spikes that obscure the small waveforms. What artifact is this and what is the best first correction?

• a.AC interference; move the patient cable away from power cords
• b.Wandering baseline; coach the patient to breathe slowly
• c.Somatic tremor; warm the patient and support the limbs✓
• d.Loose electrode; reapply the chest electrodes

Somatic tremor is muscle-movement artifact from shivering, tension, or involuntary motion, and the first correction is to warm the patient, support the arms and legs on the bed, and coach the patient to relax. Wandering baseline is a slow rolling drift rather than jagged spikes. AC interference is a uniform 60-cycle band that does not vary with how tense the patient is, and a loose electrode disturbs only the leads that electrode contributes to rather than the whole tracing.

A tracing shows the baseline slowly drifting up and down in a wave pattern that matches the patient's breathing. What should the technician check first?

• a.Whether the standardization pulse is set to 20 mm/mV
• b.Whether the patient is holding a deep breath during the whole run
• c.Whether the electrodes are loose, dried out, or over lotion✓
• d.Whether the arm and leg electrodes are reversed

A wandering baseline is usually caused by poor electrode contact from loose tabs, dried gel, body lotion, oils, or sweat, so the first check is the skin and the electrodes themselves. Respiration genuinely contributes to the drift, which is what makes breath-holding tempting, but it treats a symptom, cannot be sustained through a full 12-lead, and leaves the bad contact in place. Paper speed and standardization change the size or spacing of the complexes without causing drift, and lead reversal changes polarity rather than making the baseline roll.

What does the standardization mark on an EKG tracing indicate when it is 10 mm tall?

• a.Each large box on the paper represents 10 milliseconds
• b.The patient's voltage is ten times the normal range
• c.The paper is running at 10 mm per second
• d.One millivolt produces a 10 millimeter deflection✓

Standard calibration is 10 mm per millivolt, printed as a rectangular standardization mark two large boxes tall at the start of the tracing, so amplitudes can be compared between machines and over time. Paper speed is a separate setting, and the standard is 25 mm/sec rather than 10. The mark says nothing about the patient's own voltage, and each large box represents 0.20 second, not 10 milliseconds.

At the standard paper speed, how much time does one small box represent, and what is that speed?

• a.0.04 second at 50 mm/sec
• b.0.20 second at 25 mm/sec
• c.0.04 second at 25 mm/sec✓
• d.0.10 second at 25 mm/sec

Standard EKG paper runs at 25 millimeters per second, so each 1 mm small box equals 0.04 second and each 5 mm large box equals 0.20 second. The 0.20 second value belongs to the large box, not the small one. A speed of 50 mm/sec is a special setting used to spread out very fast rhythms, and 0.10 second does not correspond to any standard box.

How much time and voltage does one large box on standard EKG paper represent?

• a.0.50 second and 5 millimeters of height
• b.0.20 second and 5 millimeters of height✓
• c.0.04 second and 1 millimeter of height
• d.0.10 second and 10 millimeters of height

A large box is five small boxes across and five tall, so it represents 0.20 second horizontally and 5 millimeters, or 0.5 millivolt, vertically at standard calibration. The 0.04 second and 1 millimeter values describe a small box. The 0.10 and 0.50 second values do not match standard paper, where five large boxes equal one second.

A patient has a hairy chest and oily skin. What is the correct skin preparation before applying chest electrodes?

• a.Wipe with a povidone-iodine swab and apply the electrodes wet
• b.Shave the whole chest with a razor and apply lotion afterward
• c.Clip hair at each site, cleanse with alcohol, dry, then abrade lightly✓
• d.Apply the electrodes over the hair and press them down firmly

Good skin prep means clipping excess hair only at the electrode sites, cleansing with alcohol to remove oils, allowing the skin to dry completely, and lightly abrading with dry gauze to lower skin resistance. Applying electrodes over hair or onto wet skin gives poor contact and a wandering baseline. Lotion insulates the skin rather than helping it conduct, and shaving the whole chest with a razor is unnecessary and risks nicks that break the skin barrier.

A technician is setting up 5-lead telemetry monitoring. Which placement follows the standard color convention?

• a.White on the right shoulder, black on the left shoulder, green on the right lower torso, red on the left lower torso, brown on the chest✓
• b.White on the right shoulder, black on the left shoulder, red on the right lower torso, green on the left lower torso, brown on the mid-chest
• c.White on the left shoulder, black on the right shoulder, red on the left torso, green on the right torso, brown on the chest
• d.White on the right shoulder, black on the left shoulder, green on the left torso, red on the right torso, brown on the chest

The standard five-electrode convention is white on the right upper chest, black on the left upper chest, green on the right lower chest or abdomen, red on the left lower chest or abdomen, and brown as the chest electrode, remembered as white on the right, smoke over fire on the left, and clouds over grass on the right. The near-miss answer keeps the shoulders correct but swaps red and green, which reverses the lower half of the frontal plane and can invert lead II. Swapping white and black reverses lead I, and any placement that puts the wrong color on the wrong side changes the vectors the monitor computes.

How many electrodes are applied for standard 3-lead cardiac monitoring, and what do they produce?

• a.Five electrodes producing leads I, II, and III
• b.Three electrodes producing leads V1 through V3
• c.Three electrodes producing all 12 leads
• d.Three electrodes producing leads I, II, and III✓

Three-lead monitoring uses three electrodes, usually right arm, left arm, and left leg positions, and generates the three bipolar limb leads I, II, and III, with lead II most often selected because it shows P waves well. Twelve leads require ten electrodes. Five-lead systems add a ground and a chest lead, and V1 through V3 are precordial leads that a 3-lead setup cannot produce.

The QRS complexes on a 12-lead tracing are so tall that they run off the paper and overlap the lead above. What is the appropriate action?

• a.Switch to half standardization, 5 mm/mV, and mark the tracing✓
• b.Reduce the gain until the complexes match the previous tracing
• c.Increase the paper speed to 50 mm/sec and reprint the whole tracing
• d.Move the chest electrodes down one intercostal space

When complexes are too tall to fit, the machine is switched to half standardization, so 1 millivolt produces a 5 millimeter deflection, and the change is marked on the tracing so the physician can interpret amplitudes correctly. Reducing the gain by eye until the tracing resembles an earlier one is the tempting wrong answer: it changes amplitude by an undocumented amount, which destroys any comparison between the two studies. Increasing paper speed widens the complexes without lowering their height, and moving electrodes falsifies the anatomic view.

A patient's heart rate is so fast that the complexes are crowded together and hard to measure. Which machine adjustment can help, and what must the technician remember?

• a.Set the standardization to 20 mm/mV, since amplitude changes fix crowding
• b.Reduce the paper speed to 10 mm/sec, which doubles each interval
• c.Reduce the paper speed to 12.5 mm/sec, which spreads the complexes
• d.Increase the paper speed to 50 mm/sec, making each small box 0.02 second✓

Doubling the paper speed to 50 mm/sec spreads the complexes apart for easier measurement, but each small box then represents 0.02 second instead of 0.04 second, so the change must be documented or every interval will be misread as twice its true value. Slower speeds compress the tracing further, which is the opposite of what is needed, and no reduction in speed spreads complexes apart. Standardization changes amplitude, not timing, so it does nothing about complexes that are too close together.

What is the standard patient position for obtaining a resting 12-lead EKG?

• a.Sitting up with the arms folded on the chest
• b.Supine with arms at the sides and legs uncrossed✓
• c.Standing with the arms extended forward
• d.Left lateral with the knees drawn up

The standard resting EKG is taken with the patient supine, arms relaxed at the sides, legs flat and uncrossed, so muscle tension and limb contact do not distort the tracing. Folded arms and crossed legs create somatic tremor and can bridge electrodes electrically. Standing or lying on the side shifts the heart within the chest and changes waveform amplitude and axis, so any deviation from supine has to be documented on the tracing.

A patient with severe shortness of breath cannot tolerate lying flat for a 12-lead EKG. What should the technician do?

• a.Have the patient sit on the edge of the bed and hold the electrodes
• b.Postpone the test and document that the patient cannot lie flat
• c.Raise the head of the bed, obtain the tracing, and document the position✓
• d.Lay the patient flat quickly and finish before symptoms worsen

Patient comfort and safety come first, so the head of the bed is raised to a tolerable semi-Fowler position, the tracing is obtained, and the non-standard position is recorded on the tracing because it can alter waveform amplitude and axis. A documented semi-Fowler tracing is still diagnostically useful, which is why postponing the study is the wrong trade: it delays care for a test that could have been done. Forcing a dyspneic patient flat risks harm, and holding electrodes by hand introduces motion artifact and unreliable contact.

A physician orders right-sided chest leads on a patient with a suspected right ventricular infarction. Which electrode position corresponds to V4R?

• a.Fifth intercostal space, left midaxillary line
• b.Second intercostal space, right sternal border
• c.Fourth intercostal space, left sternal border
• d.Fifth intercostal space, right midclavicular line✓

Right-sided leads mirror the standard positions across the chest, so V4R sits in the fifth intercostal space at the right midclavicular line and is the single most useful lead for right ventricular infarction. The fourth space at the left sternal border is standard V2. The left midaxillary position is V6, and the second space at the right sternal border is not a chest electrode site.

A patient has a right below-the-knee amputation. How should the technician place the limb electrodes?

• a.Place both leg electrodes on the intact left leg, a few inches apart
• b.Place both leg electrodes symmetrically on the lower torso✓
• c.Move the right leg electrode to the right arm, above the elbow
• d.Omit the right leg electrode and record a nine-lead tracing

When a limb is missing, the electrode is moved to the nearest torso location on that side and the opposite limb electrode is moved to match, keeping the frontal-plane leads symmetric, and the modification is documented for the interpreting physician. Placing both leg electrodes on the remaining leg leaves them asymmetric with respect to the trunk and distorts the frontal plane. Moving a leg electrode onto an arm collapses Einthoven's triangle, and omitting the right leg electrode removes the reference the machine needs to produce a tracing at all.

When performing a 12-lead EKG on a female patient with large breast tissue, where should the V4 and V5 electrodes be placed?

• a.On the back, directly opposite the usual positions
• b.Above the breast to avoid contact with the tissue
• c.On top of the breast tissue at approximately the correct level
• d.Under the breast, on the chest wall at the correct landmarks✓

Chest electrodes are placed beneath the breast on the chest wall at the true anatomic landmarks, because breast tissue between the electrode and the heart attenuates voltage and distorts amplitude. Placing electrodes on top of the breast is the common shortcut and is exactly what causes falsely low voltage in the lateral leads. Moving them above the breast abandons the fifth intercostal space, and back placement is reserved for the special posterior leads. The patient's privacy is protected with draping throughout.

On a 12-lead tracing, leads I, II, and aVR are clean, but lead III alone shows an erratic, noisy trace. What is the most likely cause?

• a.The patient is having a myocardial infarction affecting only the inferior wall
• b.A single electrode or lead wire connection is loose or dried out✓
• c.Alternating current interference from the room lighting
• d.The paper speed is incorrect

Artifact confined to one lead points to a problem with a specific electrode or lead wire, since each limb lead uses a different combination of electrodes; the fix is to reapply that electrode and reseat the wire. A true infarction produces recognizable ST or Q wave changes across a group of leads rather than random noise. Paper speed errors and AC interference affect the entire tracing, not one lead.

A technician opens a package of disposable electrodes and finds the conductive gel is dry and crusted. What should be done?

• a.Discard the package and open fresh, unexpired electrodes✓
• b.Moisten the gel with alcohol to soften it
• c.Moisten the electrodes with tap water and use them
• d.Use them anyway and increase the gain to compensate

Dried electrodes cannot conduct properly and cause wandering baseline and unreliable amplitudes, so they are discarded and replaced with fresh electrodes from a sealed, unexpired package. Water and alcohol are not substitutes for conductive gel; alcohol in particular raises resistance once it dries. Increasing the gain amplifies the artifact along with the signal and leaves the contact problem untouched.

A tracing shows steady 60-cycle interference. Which troubleshooting sequence is most appropriate?

• a.Apply fresh electrodes and ask the patient to breathe deeply
• b.Increase the paper speed and print the tracing a second time
• c.Unplug nearby equipment and move cables off power cords✓
• d.Switch to half standardization and print the tracing again

Sixty-cycle interference comes from surrounding alternating current, so the corrections are environmental: turn off or unplug nearby devices, separate the patient cable from power cords, verify a good ground electrode, and keep the patient from touching bed rails or other metal. Paper speed and standardization changes alter how the tracing is displayed without removing the noise. Fresh electrodes fix contact problems, and deep breathing worsens baseline wander rather than removing interference.

Before beginning a shift, a technician inspects the EKG machine. Which finding requires the machine be removed from service?

• a.Electrode tabs stored in a sealed, unexpired package
• b.A standardization mark measuring exactly 10 millimeters
• c.A paper roll that is about half full
• d.A frayed patient cable with exposed wire✓

A frayed cable with exposed conductor is an electrical hazard and a source of artifact, so the machine is tagged and removed from service until repaired. A half-full paper roll is simply replaced or monitored. A 10 millimeter standardization mark is the correct calibration, and sealed unexpired electrodes are exactly what should be stocked.

What is the inherent firing rate of the sinoatrial node in a healthy adult?

• a.20 to 40 beats per minute
• b.100 to 150 beats per minute
• c.60 to 100 beats per minute✓
• d.40 to 60 beats per minute

The SA node in the upper right atrium is the heart's primary pacemaker and fires 60 to 100 times per minute, which is why normal sinus rhythm is defined by that range. The AV junction fires at 40 to 60 as a backup, and the Purkinje network fires at 20 to 40 as the last resort. A rate of 100 to 150 is a tachycardia, not an inherent pacemaker rate.

A patient's SA node fails completely. Which structure normally takes over, and at what rate?

• a.The bundle branches at 100 to 120 beats per minute
• b.The atrial muscle at 20 to 40 beats per minute
• c.The AV junction at 40 to 60 beats per minute✓
• d.The Purkinje fibers at 60 to 100 beats per minute

The AV junction is the secondary pacemaker and assumes control at 40 to 60 beats per minute when the SA node fails, producing a junctional escape rhythm with absent or inverted P waves. The Purkinje network fires only at 20 to 40 and takes over if the junction also fails. Bundle branches conduct rather than pace at a fast rate, and general atrial muscle is not a designated escape pacemaker.

What is the inherent rate of the Purkinje fibers, and what does a rhythm at that rate look like?

• a.40 to 60 beats per minute with inverted P waves
• b.20 to 40 beats per minute with wide QRS and no P waves✓
• c.100 to 150 beats per minute with sawtooth waves
• d.60 to 100 beats per minute with narrow complexes

The Purkinje network is the heart's pacemaker of last resort at 20 to 40 beats per minute, and because the impulse starts below the AV junction it spreads slowly through muscle, giving a wide QRS with no P wave in front of it. The 40 to 60 range with inverted P waves describes a junctional escape rhythm, one level higher in the conduction system. The 60 to 100 range with narrow complexes belongs to the SA node, and sawtooth waves indicate atrial flutter rather than any escape pacemaker.

What is the correct order of the cardiac electrical conduction pathway?

• a.SA node, bundle of His, AV node, Purkinje fibers, bundle branches
• b.AV node, SA node, Purkinje fibers, bundle of His, bundle branches
• c.SA node, AV node, bundle of His, right and left bundle branches, Purkinje fibers✓
• d.Purkinje fibers, bundle branches, bundle of His, AV node, SA node

The impulse begins in the SA node, spreads across the atria to the AV node, passes through the bundle of His, splits into the right and left bundle branches, and ends in the Purkinje fibers that depolarize the ventricular muscle. Any sequence that starts at the AV node or the Purkinje fibers reverses normal physiology, and the bundle of His always lies below the AV node, never above it.

Why does the impulse pause briefly at the AV node, and how does that pause appear on the EKG?

• a.To let the atria finish emptying; it is the flat part of the PR interval✓
• b.To let the coronary arteries fill before contraction; it is the ST segment
• c.To let the ventricles repolarize completely; it is seen as the T wave
• d.To slow the SA node so that it cannot fire too quickly; it is the TP segment

The AV node delays the impulse about a tenth of a second so the atria can complete their contraction and top off ventricular filling before the ventricles fire, and that delay is the flat portion of the PR interval between the end of the P wave and the start of the QRS. The T wave represents ventricular repolarization, which happens after the ventricles have already contracted. The ST segment sits between ventricular depolarization and repolarization, and the AV node does not regulate the rate of the SA node.

What is depolarization?

• a.The closing of the atrioventricular valves in systole
• b.Electrical discharge of the cardiac cells before contraction✓
• c.The filling of the coronary arteries in diastole
• d.The relaxation of cardiac muscle as it returns to rest

Depolarization is the rapid electrical change across the cell membrane that triggers mechanical contraction, and it produces the P wave in the atria and the QRS complex in the ventricles. Electrical recovery and relaxation are repolarization, which is the opposite half of the cycle. Coronary filling and valve closure are mechanical events of the cardiac cycle, and an EKG does not record either of them.

A student asks why an EKG can look normal in a patient whose heart is not pumping effectively. What is the best explanation?

• a.The EKG measures blood pressure rather than electrical activity
• b.EKG machines are frequently inaccurate when cardiac output is low
• c.Electrical activity can occur without effective contraction✓
• d.The EKG records only atrial activity and not ventricular output

An EKG records only the electrical events of the heart, so an organized rhythm can appear on the monitor while the heart produces no pulse, a situation called pulseless electrical activity. This is exactly why the technician confirms the patient's condition rather than treating the monitor. The machine is not measuring pressure or output at all, so it is not a question of accuracy, and the tracing records both atrial and ventricular electrical activity.

What is the correct path of blood through the heart, starting with deoxygenated blood returning from the body?

• a.Right atrium, mitral valve, right ventricle, aorta, lungs, left atrium, tricuspid valve, left ventricle
• b.Right ventricle, right atrium, lungs, left ventricle, left atrium, aorta
• c.Right atrium, tricuspid valve, right ventricle, pulmonic valve, lungs, left atrium, mitral valve, left ventricle, aorta✓
• d.Left atrium, mitral valve, left ventricle, lungs, right atrium, tricuspid valve, right ventricle, aorta

Deoxygenated blood enters the right atrium from the venae cavae, passes the tricuspid valve into the right ventricle, leaves through the pulmonic valve to the lungs, returns oxygenated to the left atrium, crosses the mitral valve into the left ventricle, and exits through the aortic valve to the body. The mitral valve is always on the left and the tricuspid on the right, and blood always flows atrium to ventricle, never the reverse.

Which valve separates the right atrium from the right ventricle?

• a.Aortic valve
• b.Pulmonic valve
• c.Tricuspid valve✓
• d.Mitral valve

The tricuspid valve, named for its three cusps, lies between the right atrium and right ventricle and prevents backflow during ventricular systole. The mitral valve is the corresponding atrioventricular valve on the left side. The pulmonic and aortic valves are semilunar valves that guard the exits from the right and left ventricles.

When does blood flow into the coronary arteries to supply the heart muscle itself?

• a.During ventricular diastole, when the muscle is relaxed✓
• b.Only during atrial contraction, in late diastole
• c.During ventricular systole, when pressure is highest
• d.Continuously and equally through the cardiac cycle

The coronary arteries branch from the base of the aorta and fill mainly during diastole, because during systole the contracting myocardium squeezes the vessels running through it. This is one reason very fast heart rates, which shorten diastole most, can provoke ischemia. Atrial contraction contributes to ventricular filling rather than coronary perfusion, and coronary flow is distinctly phasic rather than constant.

How is cardiac output calculated?

• a.Heart rate divided by stroke volume
• b.Heart rate multiplied by stroke volume✓
• c.Stroke volume multiplied by blood pressure
• d.Systolic pressure minus diastolic pressure

Cardiac output equals heart rate times stroke volume, the amount of blood ejected by the left ventricle each beat, and it is normally about 4 to 8 liters per minute in an adult. Subtracting diastolic from systolic pressure gives pulse pressure. Dividing rate by stroke volume or multiplying stroke volume by blood pressure produces no meaningful physiologic measurement.

What happens during ventricular diastole?

• a.Blood is forced into the aorta and pulmonary artery
• b.The atrioventricular valves snap shut
• c.The ventricles relax and fill with blood✓
• d.The ventricles contract and eject blood

Diastole is the relaxation and filling phase, during which the atrioventricular valves are open and blood flows from the atria into the ventricles. Contraction and ejection define systole. The atrioventricular valves close at the start of systole, and blood enters the great vessels only when the ventricles contract.

A patient arrives with crushing chest pain radiating to the left jaw. The 12-lead shows ST segment elevation in leads II, III, and aVF. What does this pattern most likely represent?

• a.Benign early repolarization in a young adult
• b.Acute pericarditis with diffuse ST elevation
• c.Acute infarction of the inferior wall✓
• d.Left atrial enlargement with a notched P

ST segment elevation confined to a group of anatomically related leads is the classic sign of acute myocardial injury, and leads II, III, and aVF all look at the inferior wall of the left ventricle. Pericarditis is the answer worth taking seriously, because it also elevates the ST segment, but it typically does so diffusely across leads from several different territories rather than in one region. The technician does not diagnose either one, but must recognize the pattern and notify the nurse or physician immediately. Atrial enlargement changes the P wave rather than the ST segment.

How does stable angina differ from a myocardial infarction?

• a.Angina causes permanent muscle death, while an infarction is reversible
• b.Angina occurs only at rest, while an infarction occurs with exertion
• c.Angina shows ST elevation, while an infarction shows ST depression
• d.Angina is reversible ischemia; an infarction kills muscle✓

Angina is chest pain from a temporary oxygen shortage in the myocardium, typically brought on by exertion and relieved within minutes by rest or nitroglycerin, and it may show transient ST depression or T wave inversion. A myocardial infarction is a sustained occlusion that kills muscle tissue and often produces ST elevation and, later, pathologic Q waves. The answers that reverse the two have the relationship backward: it is the infarction that causes permanent damage, and it is stable angina, not infarction, that is predictably provoked by exertion.

A patient scheduled for an EKG has ankle swelling, shortness of breath when lying flat, and a history of congestive heart failure. What is happening physiologically?

• a.The SA node has stopped firing and an escape rhythm has taken over
• b.The conduction system has been interrupted below the AV node
• c.The heart cannot pump well, so blood backs up behind it✓
• d.The coronary arteries are completely blocked by a fresh clot

In congestive heart failure the weakened ventricle cannot move the volume delivered to it, so fluid backs up behind the failing side, producing pulmonary congestion and orthopnea on the left and dependent edema on the right. Complete coronary occlusion describes an acute infarction, which presents with pain over minutes to hours rather than chronic swelling. SA node failure produces an escape rhythm, and a conduction block changes the rhythm without by itself causing fluid overload.

Long-standing untreated hypertension most commonly produces which EKG-related change?

• a.Absent P waves with an irregularly irregular ventricular response
• b.Pacemaker spikes in front of every QRS complex on the tracing
• c.A QT interval shortened to less than 0.20 second at any rate
• d.Left ventricular hypertrophy with tall left-sided R waves✓

Chronic high blood pressure forces the left ventricle to work against increased resistance, so the muscle thickens and generates larger voltage, appearing as tall R waves in the left-sided leads and deep S waves in V1 and V2. Atrial fibrillation is a genuine long-term complication of hypertension, but absent P waves are not the change hypertension most commonly produces, and the question asks for the usual finding. A QT under 0.20 second is not a hypertensive finding, and pacemaker spikes come from an implanted device.

Which layer of the heart wall is the thick muscular layer responsible for contraction?

• a.Myocardium✓
• b.Epicardium
• c.Pericardium
• d.Endocardium

The myocardium is the middle, muscular layer whose contraction generates the pumping force, and it is the tissue damaged in a myocardial infarction. The endocardium is the thin inner lining in contact with the blood. The epicardium is the outer surface layer of the heart, and the pericardium is the surrounding sac.

Why is the left ventricle the thickest chamber of the heart?

• a.It must generate the pressure for the entire systemic circuit✓
• b.It holds a much larger volume of blood than the other chambers
• c.It houses the SA node and needs extra muscle for protection
• d.It receives all of the blood returning through the venae cavae

The left ventricle pumps against the high resistance of the systemic circuit, so its wall is roughly three times thicker than the right ventricle, which only has to move blood to the nearby low-pressure lungs. Both ventricles eject about the same volume with each beat, so chamber volume is not the reason for the difference. The SA node sits in the right atrium, and the venae cavae empty into the right atrium as well.

Before performing an EKG on an inpatient, how should the technician identify the patient?

• a.Ask the family member at the bedside to confirm who the patient is
• b.Check that the room number and bed number match the order sheet
• c.Call the patient by name and proceed if the patient answers to it
• d.Have the patient state name and birth date and check the band✓

Two patient identifiers, most commonly full name and date of birth verified against the armband and the order, are the accepted standard, and the patient states them rather than confirming a name that is read aloud. Room and bed numbers change with transfers and are never acceptable identifiers. Patients may answer to the wrong name when medicated, confused, or hard of hearing, and confirmation by a family member does not replace the two required identifiers.The Joint Commission National Patient Safety Goal 01.01.01

An EKG technician looks up the chart of a coworker who was admitted overnight, out of concern for her wellbeing. Is this permitted?

• a.Yes, because a personal friendship gives a legitimate reason to look
• b.Yes, because employees may view records at the facility that employs them
• c.No; access without a treatment or operations purpose is a violation✓
• d.Yes, as long as the technician does not repeat what she reads

Federal privacy rules limit access to protected health information to what a person needs for their own job duties, so browsing a coworker's chart out of curiosity or concern is a reportable violation regardless of intent. Employment grants access only to the records needed for assigned work, not to the whole system. Keeping the information secret afterward does not cure the improper access, and a personal relationship is not a permitted purpose.HIPAA

Two technicians are discussing a patient's abnormal EKG in a crowded elevator. What is the problem?

• a.It is a problem only if a member of the patient's family is present
• b.Nothing, as long as they avoid using the patient's first and last name
• c.Nothing is wrong, because both of them work for the same facility
• d.Protected health information can be overheard by unauthorized people✓

Discussing a patient where visitors and unrelated staff can overhear is an improper disclosure of protected health information, and clinical conversations belong in private areas. Omitting the name does not protect a patient who is still identifiable from the room, the diagnosis, or the context. Being coworkers permits discussion only when there is a treatment need and a private setting, and the violation exists whether or not a relative happens to be in the elevator.HIPAA

When must an EKG technician perform hand hygiene?

• a.Before and after every patient contact and after glove removal✓
• b.Only after contact with blood or other potentially infectious fluid
• c.Only at the beginning and at the end of each scheduled work shift
• d.Only when the hands look or feel visibly soiled during the shift

Hand hygiene is required before and after every patient contact, after glove removal, and after touching potentially contaminated surfaces or equipment, because gloves can have unseen defects and hands become contaminated during removal. Waiting for a blood or fluid exposure ignores the routine transfer of organisms from intact skin and from equipment. Visible soil is a reason to wash but not the threshold for washing, and shift-based washing leaves every patient in between unprotected.CDC Guideline for Hand Hygiene in Health-Care Settings

A patient's chest has an open, draining wound near a chest electrode site. What does the bloodborne pathogens standard require of the technician?

• a.No special measures are needed, because an EKG is a noninvasive test
• b.Apply the electrode directly over the wound to keep placement accurate
• c.Postpone the test and send the patient home until the wound has healed
• d.Treat the drainage as infectious and keep electrodes off the site✓

The bloodborne pathogens standard requires that all blood and other potentially infectious material be treated as infectious, so gloves and any other indicated protective equipment are worn and contaminated items are disposed of properly. Electrodes are not applied over broken or draining skin; the site is shifted slightly and the change is documented. A noninvasive test does not exempt the technician from precautions, and postponing an ordered test because of a wound withholds care that can be given safely.OSHA 29 CFR 1910.1030

A patient asks the EKG technician, "Does this tracing mean I had a heart attack?" What is the appropriate response?

• a.Explain that the physician reads the tracing, and tell the nurse✓
• b.Hand the tracing to the patient so that he can read it for himself
• c.Reassure the patient that the tracing looks completely normal to you
• d.Tell the patient that the tracing looks like a heart attack to you

Interpreting and diagnosing are outside the EKG technician's scope of practice, so the appropriate response refers the question to the provider, acknowledges the patient's concern, and passes the question along to the nurse. Offering a reassuring reading is as far outside scope as offering an alarming one, and either may turn out to be wrong. Releasing the tracing directly to the patient bypasses both the provider and the facility's record release process.

While attaching electrodes, the technician sees ventricular fibrillation appear on the screen and the patient becomes unresponsive. What is the first action?

• a.Document the time and the rhythm in the patient's medical record
• b.Finish the 12-lead tracing so the physician has a complete record
• c.Call for help, activate the emergency response, and start CPR✓
• d.Reposition the electrodes first to rule out a movement artifact

Ventricular fibrillation in an unresponsive patient is a cardiac arrest, and survival depends on immediate activation of the emergency response followed by prompt CPR and defibrillation. Checking for artifact is the right instinct in the wrong patient: it applies when the person is awake and stable, and this patient is not. Completing the tracing or documenting first spends the minutes that determine the outcome.

During a treadmill stress test, the patient reports chest pain and the monitor shows new ST segment depression. What should the technician do?

• a.Tell the patient that chest discomfort is expected and continue the stage
• b.Stop the test, notify the supervising provider, and keep monitoring✓
• c.Turn the monitor away so that the patient does not become anxious
• d.Increase the treadmill speed to finish the protocol stage

New chest pain or significant ST changes are recognized indications to terminate a stress test, and the supervising provider is notified at once while the patient continues to be monitored through recovery. Advancing the protocol raises myocardial oxygen demand at exactly the moment the heart is showing it cannot meet demand. Dismissing the symptom is unsafe, and turning the monitor away removes the information needed to manage the event.

Which information must appear on every EKG tracing?

• a.The technician's home phone number and the machine's serial number only
• b.The patient's next scheduled appointment date and the clinic's location
• c.The patient's admitting diagnosis and the name of the insurance carrier
• d.The patient's name and identifier, the date and time, and who took it✓

A tracing is a legal part of the medical record and must identify the patient, the exact date and time it was taken, and the person who took it, along with any deviation such as altered electrode placement or a non-standard setting. Diagnoses are supplied by the interpreting physician rather than the technician. Insurance and appointment details belong elsewhere in the record, and personal contact information for staff is never placed on a tracing.

What is appropriate routine maintenance for EKG equipment between patients?

• a.Clean the machine only when it looks visibly soiled or sticky
• b.Wipe the machine and cables with an approved disinfectant✓
• c.Wrap the lead wires tightly around the machine to save space
• d.Submerge the entire patient cable in a disinfectant solution

Between patients the machine surfaces, cables, and any reusable components are wiped with a facility-approved disinfectant, the wires are inspected for cracks and gently uncoiled, and supplies are restocked so the unit is ready for the next study. Immersing a patient cable ruins the connectors and creates an electrical hazard. Wrapping wires tightly breaks the internal conductors and causes artifact, and waiting for visible soil ignores contamination that cannot be seen.

A patient is being fitted with a 24-hour Holter monitor. Which instruction is correct?

• a.Keep a diary of activities and symptoms with the times they occur✓
• b.Avoid all physical activity so that the recording stays clean
• c.Take the monitor off for showers and write down the time
• d.Remove the electrodes at bedtime and reapply them the next morning

The value of a Holter study comes from matching recorded rhythm changes to the patient's diary of activities and symptoms, so accurate timed entries are essential, and the recorder stays on and dry for the whole recording period. Removing electrodes for a shower or overnight creates gaps in exactly the hours the study is trying to capture. Patients are told to follow their usual routine rather than to rest, because the point is to record everyday events.

What is the purpose of telemetry monitoring?

• a.It records the patient's heart sounds for a physician to review later
• b.It records a permanent 12-lead tracing once during every shift
• c.It sends the rhythm continuously to a central monitoring station✓
• d.It measures the blood pressure automatically every fifteen minutes

Telemetry uses a small battery-powered transmitter worn by the patient to send the cardiac rhythm wirelessly to a central station, allowing continuous observation while the patient moves about the unit. A 12-lead EKG is a separate diagnostic study recorded on a stationary machine, not something telemetry produces. Automated blood pressure monitoring and heart sound recording use entirely different equipment.

Which instructions should a patient receive before a scheduled exercise stress test?

• a.Stop taking all prescription medications for one week before the test
• b.Avoid food, caffeine, and tobacco as directed; wear walking shoes✓
• c.Wear dress shoes and take all usual medications without mentioning them
• d.Eat a large meal beforehand and drink strong coffee for extra energy

Standard stress test preparation includes fasting and avoiding caffeine and tobacco for the period the facility specifies, wearing comfortable two-piece clothing and supportive walking shoes, and reviewing current medications with the provider, since drugs such as beta blockers blunt the heart rate response. Patients do not stop medications on their own; that decision belongs to the ordering provider and stopping some drugs abruptly is dangerous. Eating heavily or drinking coffee alters the result, and dress shoes are unsafe on a treadmill.

An anxious patient is trembling and asks whether the EKG will shock her. What is the best response?

• a.Explain simply that the machine records and delivers no current✓
• b.Explain the electrical engineering of the machine in full technical detail
• c.Have her sign the consent form and then start the test without discussion
• d.Tell her there is nothing at all to worry about and start attaching leads

A clear, simple explanation lowers anxiety, and a relaxed patient also produces a tracing free of somatic tremor artifact, so communication here is both a professional and a technical necessity. Dismissing the concern leaves the patient frightened and tense, which shows up in the tracing. An overly technical explanation confuses rather than reassures, and collecting a signature without answering the question is not informed cooperation.

A competent adult patient refuses to allow an ordered EKG. What should the technician do?

• a.Tell the patient that he will be billed for the refused test
• b.Stop, respect the refusal, and notify the nurse or provider✓
• c.Perform the test anyway, because the physician has ordered it
• d.Have a family member give permission instead

A competent adult has the right to refuse any procedure, and proceeding without consent could constitute battery, so the technician stops, reports the refusal to the nurse or ordering provider, and documents what happened. A physician order authorizes the test but does not override the patient's decision. Threatening the patient with a charge is coercion, and a family member cannot consent on behalf of a competent adult.

A technician sustains a needlestick-free but bloody scratch from a broken bed rail while positioning a patient. What is the required response?

• a.Finish the EKG and mention it to someone at the end of the shift
• b.Document the incident in the patient's chart and then keep working
• c.Wash the area and report the exposure to the supervisor at once✓
• d.Cover it with a glove and continue with the rest of the patients

The bloodborne pathogens standard requires that an exposure incident be washed immediately and reported without delay, so the employer can provide a confidential medical evaluation and any indicated post-exposure follow-up, which is time-sensitive and loses effectiveness with every hour. Waiting until the shift ends can forfeit that protection. Covering the wound and continuing risks both the technician and the patients, and an employee exposure is recorded in an incident report rather than in the patient's chart.OSHA 29 CFR 1910.1030

A technician notices she wrote the wrong date on a completed paper EKG record. How should the correction be made?

• a.Shred the record and print a new one without noting that it changed
• b.Erase the wrong entry neatly and then write the correct date over it
• c.Draw a single line through the error, correct it, and initial it✓
• d.Cover the error with correction fluid and write the new date over it

A legal health record is corrected by drawing one line through the error so it stays readable, entering the correct information, and initialing and dating the change, which preserves an honest audit trail. Erasing or covering the entry destroys the original and looks like concealment even when the intent is innocent. Destroying a record and silently replacing it is falsification of a medical record.

An outpatient's routine 12-lead shows a run of ventricular tachycardia, but the patient feels fine and asks to leave. What should the technician do?

• a.Keep the patient in the department and notify the provider at once✓
• b.Repeat the tracing until a normal one prints, then release him
• c.Give the patient the tracing to take to his next appointment
• d.Reassure the patient, let him leave, and file the tracing

A critical finding such as a run of ventricular tachycardia is reported to the provider immediately and the patient is kept under observation, because a patient who feels well can deteriorate without warning. Filing the tracing for later review delays urgent care by hours or days. Repeating the study until it looks normal conceals a real finding, and handing the tracing to the patient moves a clinical responsibility onto someone who cannot act on it.

Which action best reflects professional behavior for an EKG technician?

• a.Introduce herself by name and title and work within her scope✓
• b.Perform a lab draw because the unit is short staffed tonight
• c.Post an interesting anonymized rhythm strip on social media
• d.Tell the patient's spouse the results while the patient is away

Professionalism means identifying yourself and your role, explaining what you are about to do, and working strictly within your training and scope of practice. Posting strips online risks re-identification and violates patient privacy even when names are removed. Sharing results with a spouse without authorization is an improper disclosure, and performing an untrained procedure exceeds scope no matter how short staffed the unit is.

A technician is asked to point out the PR segment on a 12-lead tracing. Which portion of the tracing is the PR segment?

• a.The stretch from the beginning of the P wave to the beginning of the QRS complex
• b.The stretch from the end of the QRS to the beginning of the T wave
• c.The flat stretch from the end of the P wave to the beginning of the QRS✓
• d.The flat stretch from the end of the T wave to the next P wave

The PR segment is the flat piece of baseline that begins where the P wave ends and stops where the QRS begins; it corresponds to the conduction delay in the AV node and bundle of His. Measuring from the start of the P wave instead gives the PR interval, which includes the P wave and normally runs 0.12 to 0.20 second, so that answer describes an interval rather than a segment. The stretch from the end of the QRS to the start of the T wave is the ST segment, and the flat piece from the end of the T wave to the next P wave is the TP segment.

On a 12-lead tracing, which landmark marks the end of the QRS complex and the start of the ST segment?

• a.The J point, evaluated in each of the twelve leads✓
• b.The peak of the R wave, the tallest upward deflection
• c.The isoelectric baseline between two consecutive beats
• d.The end of the PR interval, just before the QRS

The J point is the junction where the last deflection of the QRS ends and the ST segment begins, and ST elevation or depression is judged at or just after it. The peak of the R wave sits in the middle of ventricular depolarization, not at its end. The isoelectric baseline is the flat reference line the tracing rests on between beats, not a landmark on the complex itself. The end of the PR interval is a real landmark, but it marks the onset of the QRS rather than its offset.

A technician needs a reference line to judge whether an ST segment sits above or below baseline. Which part of the tracing supplies that isoelectric reference?

• a.The peak of the T wave that follows the segment being measured
• b.The top of the tallest R wave recorded anywhere on the strip
• c.The PR interval, measured from the start of the P wave to the QRS
• d.The TP segment, the flat line from the end of the T wave to the next P wave✓

The TP segment is electrically silent, so it is the flat baseline against which ST deviation is measured. The PR interval is not a reference line at all, because it spans the P wave and the PR segment together and is measured as a duration; the flat PR segment alone can substitute as a baseline when a fast rate leaves almost no TP segment. The peak of the T wave and the top of an R wave are deflections away from baseline, so neither can define where the isoelectric line lies.

Which description states correctly where a QT interval starts and where it ends?

• a.From the beginning of the P wave to the end of the T wave
• b.From the end of the P wave to the point where the T wave ends
• c.From the beginning of the QRS complex to the end of the T wave✓
• d.From the first deflection of the QRS to the point where the T wave peaks

The QT interval runs from the earliest onset of the QRS complex, whether that first deflection is a Q wave or an R wave, to the point where the T wave returns to the isoelectric line, and it is read in the lead where the end of the T wave is clearest, often lead II or V5. Starting at the onset of the P wave adds the whole PR interval and overstates the measurement. Starting at the end of the P wave still includes the PR segment, so it also runs long. Stopping at the peak of the T wave cuts the measurement short, because repolarization is not finished until the T wave has come back to the baseline.

On a regular strip, one R wave falls on a heavy line and the next R wave falls midway between the fourth and fifth heavy lines after it. What is the approximate ventricular rate?

• a.Exactly 75 beats per minute, the value at the fourth heavy line
• b.About 67 beats per minute, between the 75 and 60 values✓
• c.Exactly 60 beats per minute, the value at the fifth line
• d.About 45 beats per minute, since the boxes are wide

The sequence method assigns 300, 150, 100, 75, 60, 50 to successive heavy lines, so an R wave landing between the fourth and fifth lines falls between 75 and 60 beats per minute. Dividing 300 by the 4.5 large boxes actually measured gives 66.7, which rounds to about 67. Reading the fourth line as 75 or the fifth line as 60 forces the R wave onto a line it did not reach. A rate near 45 would require more than six large boxes between R waves.

During a 12-lead acquisition the baseline drifts slowly up and down across the paper in the limb leads while the patient breathes deeply and shifts on the table. What should the technician do first?

• a.Report the drifting baseline to the supervisor before repeating the tracing
• b.Secure the limb electrodes on flat skin, ask the patient to lie still, and repeat✓
• c.Record the tracing anyway and note that the patient was breathing deeply
• d.Switch the machine to the 50 mm/sec setting to flatten the baseline

A slow, rolling baseline is wandering-baseline artifact, and it comes from patient motion, deep respiration, or electrodes that are loose, dried out, or sitting over skin that was not prepared. Correcting the cause and repeating the tracing is inside the technician's own scope and takes seconds, so raising it with a supervisor first delays the study without fixing anything. Submitting a drifting tracing with a note leaves an uninterpretable ST segment for the reader. Doubling the paper speed stretches the complexes horizontally but does nothing to the drift and makes the tracing nonstandard.

A technician analyzes every strip the same way, beginning with the rate and then the regularity. In a standard five-step analysis, what is examined next?

• a.The width of the QRS complexes, measured in small boxes
• b.Whether a uniform P wave precedes each QRS complex✓
• c.The PR interval, counted in small boxes
• d.The shape of the T wave in that same lead

The usual five steps are rate, regularity, P waves, PR interval, and QRS duration, so the P waves come third. Looking at the P waves first is what makes the PR interval meaningful, because a PR interval cannot be measured until an atrial wave has been identified and shown to be uniform and upright. QRS duration is the fifth step and separates supraventricular from ventricular complexes. T wave shape is part of a physician's interpretation and is not one of the five measured steps.

A strip shows P waves marching out at their own regular rate and QRS complexes at a slower regular rate. How should the technician determine the atrial rate?

• a.Count the QRS complexes in a six-second strip and multiply the total by ten
• b.Divide 1500 by the number of small boxes between a P wave and the QRS after it
• c.Subtract the ventricular rate from 300 to get the rate of the atria
• d.Measure from one P wave to the next and apply a rate method✓

When the atria and the ventricles are firing independently, two rates exist and each is measured from its own waves: the atrial rate from P-P intervals and the ventricular rate from R-R intervals. Counting QRS complexes gives only the ventricular rate and says nothing about how fast the atria are firing. Measuring from a P wave to the following QRS measures the PR interval, which is a conduction time and not a cycle length. Subtracting from 300 has no basis; the 300 is a count of large boxes per minute, not a rate that can be split between chambers.

Every lead of a 12-lead tracing shows a thick, fuzzy baseline of fine, perfectly regular oscillations. The patient is comfortable and lying still, and the complexes are still visible through the fuzz. What should the technician do first?

• a.Report the fuzzy baseline to the supervisor and wait for further direction
• b.Ask the patient to hold still and breathe quietly during the repeat
• c.Move nearby electrical equipment away and untangle the lead wires✓
• d.Raise the calibration to 20 mm/mV so the complexes stand out

A uniform, perfectly regular fuzz in every lead of a still patient is alternating-current interference picked up from nearby powered equipment or from lead wires running alongside power cords. Separating the wires from power cords, unplugging or moving the offending device, and confirming the cable connections is the technician's own first step. Asking a patient who is already lying still to hold still addresses somatic tremor artifact instead, which is coarse and irregular rather than uniform. Doubling the calibration magnifies the interference along with the complexes and makes the tracing nonstandard, and handing the problem to a supervisor delays a fix the technician can make.

A telemetry strip on a patient with a low potassium level and a heart rate of 52 shows an extra small, rounded, upright deflection in every cardiac cycle, most prominent in leads V2 and V3. What is this deflection called?

• a.An early P wave from the next beat
• b.A U wave following the T wave✓
• c.A biphasic T wave with two peaks
• d.A J point elevated above baseline

A small rounded wave that comes after the T wave and shares its direction is a U wave, best seen in leads V2 and V3, and it becomes prominent with a low potassium level and with slow heart rates. A premature P wave would fall early in the cycle and would be followed by its own QRS complex rather than appearing once in every cycle. A biphasic T wave has one positive and one negative component within a single wave rather than a separate rounded deflection after the T wave returns to baseline. The J point lies at the far end of the QRS, well before the T wave.

A ventricular complex on a strip is entirely negative: it begins with a downward deflection and no upward deflection appears anywhere in it. How is this complex named?

• a.A Q wave followed immediately by an S wave
• b.An R wave inverted below baseline
• c.A QS complex, with no R wave present✓
• d.A deep S wave without a Q wave

Naming depends on the R wave: a Q wave is a negative deflection before the first R wave and an S wave is a negative deflection after an R wave, so with no R wave at all there is nothing to place a Q before or an S after, and the whole complex is called a QS complex. Calling it a Q followed by an S is the common trap, because it would require an R wave between them. An R wave is positive by definition, so there is no such thing as an inverted R wave. Calling it an S wave alone has the same problem in reverse, since an S wave must follow an R wave.

In lead V1 a complex shows a small upward deflection, then a downward deflection, then a second upward deflection. How is that second upward deflection labeled?

• a.An S wave, because it follows the first negative deflection
• b.A J point elevation on the tail end of the complex
• c.An R prime wave, the second positive deflection✓
• d.A U wave riding on the end of the complex

Any positive deflection after the first one is labeled R prime, so this complex is written as rSR prime, the pattern often seen in V1. An S wave is negative by definition and cannot name an upward deflection. J point elevation is a shift of the baseline where the QRS ends, not an added wave inside the complex. A U wave appears after the T wave has finished, separated from the QRS by the ST segment and the T wave.

In a normally conducted sinus rhythm, how should the P wave appear in lead II and in lead aVR?

• a.Inverted in lead II, upright in aVR
• b.Upright in lead II and inverted in lead aVR✓
• c.Upright in both lead II and lead aVR
• d.Flat in lead II and biphasic in aVR

A sinus impulse starts high in the right atrium and spreads downward and to the left, toward the positive electrode of lead II and away from the positive electrode of aVR, so the sinus P wave is upright in lead II and inverted in aVR. An inverted P wave in lead II means the atria were depolarized from below, as happens when the pacemaker site sits low in the atria or in the junction. An upright P wave in aVR is a separate warning sign and most often means limb electrodes have been reversed, so it should send the technician back to check the arm and leg placements before the tracing is submitted. A flat P wave in lead II usually means the atrial activity is too small to see in that lead rather than that conduction is normal.

Across an entire strip the R-R intervals repeat the same pattern of two short intervals followed by one long interval. How is this regularity described?

• a.Regularly irregular✓
• b.Irregularly irregular
• c.Occasionally irregular
• d.Regular with a pause

An irregular rhythm whose irregularity repeats in a predictable cycle is called regularly irregular, and grouped beating like this is the reason a technician measures several R-R intervals across the whole strip rather than one pair. Irregularly irregular describes R-R intervals that vary with no repeating pattern, which is not what a repeating two-short-one-long sequence does. Occasionally irregular fits a rhythm that is regular except for isolated ectopic beats. Calling it regular with a pause would require the underlying R-R intervals to be constant, and here they are not.

A woman started on a new antiarrhythmic has a regular sinus rhythm at 60 beats per minute, and her QT interval measures 0.48 second. What should the technician do with this measurement?

• a.Report the long QT to the supervisor and document it✓
• b.Tell the patient the new medication is unsafe for her
• c.Record the QT from the lead where the T wave ends first
• d.Repeat the tracing at 50 mm/sec so the QT measures shorter

At 60 beats per minute the R-R interval is exactly one second, and the square root of one is one, so the corrected QT equals the measured 0.48 second, above the roughly 0.46-second upper limit used for women. A prolonged QT on a patient starting an antiarrhythmic is a finding the technician reports promptly through the chain of command and documents, since a CET acquires and reports but does not diagnose or advise on therapy. Telling the patient the drug is unsafe is interpreting for the patient and is outside the technician's scope. Choosing the lead with the earliest T wave ending hides the longest QT, and doubling the paper speed only widens the tracing; the measured duration in seconds does not change.

A monitored patient who is awake and talking has a sinus rhythm at 68 beats per minute interrupted by a 4-second stretch with no P wave and no QRS complex, after which sinus rhythm resumes. What should the technician do?

• a.Print the strip and report the pause to the supervisor at once✓
• b.Raise the low-rate alarm limit so the monitor stops alarming
• c.Wait to see whether the pause repeats before telling anyone
• d.Chart the pause as artifact from the patient turning over in bed

A pause with no atrial and no ventricular activity is a sinus arrest, and under typical monitoring policy a pause beyond about three seconds is printed, documented, and reported to the nurse or supervisor without waiting, even in a patient who currently feels well. Waiting for a second event trades away the time a longer pause would cost. Raising the alarm limit suppresses the very event the monitor exists to catch. Calling it artifact does not fit, because motion artifact leaves a noisy baseline rather than a clean flat line that ends with the sinus rhythm resuming.

A sinus rhythm at 75 beats per minute is interrupted by one missing P-QRS pair, and the pause measures exactly twice the underlying P-P interval before the sinus rhythm resumes on schedule. What does this pattern suggest?

• a.A sinoatrial exit block dropped one P-QRS cycle✓
• b.Sinus arrest, with the sinus node failing to fire
• c.An atrial beat that arrived early and did not conduct
• d.A dropped beat from a second-degree AV block

In sinoatrial exit block the sinus node keeps firing on time but one impulse fails to leave the node, so the pause equals an exact multiple of the underlying P-P interval and the next P wave lands right where the caliper predicts. In sinus arrest the node itself stops, and the pause has no arithmetic relationship to the P-P interval, so the rhythm usually resumes off schedule. A nonconducted early atrial beat would show a premature P wave, often hidden in the preceding T wave, before the pause. A dropped beat from AV block would leave a P wave standing alone with no QRS after it, whereas here the P wave is missing along with the QRS.

A tracing was recorded at a paper speed of 50 mm/sec. On a regular rhythm the R waves are five large boxes apart. What is the patient's actual heart rate?

• a.60 beats per minute, read the way a 25 mm/sec strip is read
• b.About 30 beats per minute, because the paper ran twice as fast
• c.150 beats per minute, using the sequence method on this strip
• d.120 beats per minute, because each large box here is 0.10 second✓

Doubling the paper speed halves the time each box represents, so at 50 mm/sec a small box is 0.02 second and a large box is 0.10 second. Five large boxes is therefore 0.50 second, and 60 divided by 0.50 gives 120 beats per minute. Reading the strip as though it ran at 25 mm/sec yields 60 and halves the true rate, which is the error this speed most often causes. Halving again to 30 compounds that mistake, and the memorized sequence values apply only at 25 mm/sec.

A patient with a resting hand tremor produces a strip whose limb leads carry a fine, jagged, irregular baseline. The chest leads are clean, the R-R intervals are regular, and an upright P wave precedes every QRS. What is the most likely explanation?

• a.Atrial fibrillation with a fine fibrillatory baseline
• b.Atrial flutter at a rate the monitor cannot count
• c.Muscle tremor artifact from the patient's hand✓
• d.Interference from nearby electrical equipment

Somatic tremor artifact produces an irregular, spiky baseline that appears in the leads sharing the trembling limb and spares leads that do not, and the underlying rhythm shows through it unchanged. Regular R-R intervals with an upright P wave before each QRS rule out atrial fibrillation, which is irregularly irregular and has no P waves. Flutter waves are uniform sawtooth deflections at a regular atrial rate near 300 per minute, not the ragged tracing described. Alternating-current interference would be uniform and perfectly regular and would appear in every lead rather than in the limb leads alone.

A technician wants to know whether the P waves continue on schedule through a pause on a strip. How are calipers used to check that?

• a.Set the points on a P wave and the QRS that follows it, then step across
• b.Set the points on two consecutive P waves, then step that width across the pause✓
• c.Set the points on the tallest R waves and compare that width to the pause
• d.Set the points on the width of one P wave and count how many fit

Marching out the atrial rhythm means fixing the calipers on the P-P interval of two conducted beats and then stepping that same distance forward, which shows whether the next P wave arrives where the sinus node would have placed it. Setting the points on a P wave and the QRS after it measures the PR interval, a conduction time that says nothing about atrial timing. Using R waves marches out the ventricular rhythm, which is a separate measurement and can stay regular while the atrial rhythm does not. The width of a single P wave is its duration, not a cycle length, so counting how many fit in a pause measures nothing useful.

During tracheal suctioning a monitored patient's rate falls from 74 to 46 beats per minute. Upright P waves still precede every narrow QRS with a PR interval of 0.16 second, and the rate returns to 74 once suctioning stops. What best explains the slowing?

• a.A junctional escape rhythm took over during suctioning
• b.Vagal stimulation slowed the rate of the sinus node✓
• c.The sinus node stopped and an atrial focus took over
• d.A second-degree block dropped every other beat

Suctioning, vomiting, gagging, and bearing down all stimulate the vagus nerve, which slows the sinus node and produces a transient sinus bradycardia that resolves when the stimulus ends. The P waves stayed upright with a normal PR interval, so the sinus node is still the pacemaker, which rules out a junctional escape rhythm and an ectopic atrial focus; both would change the shape of the P wave or its timing relative to the QRS. A second-degree block dropping alternate beats would leave P waves standing alone with no QRS after them, and none are described. The technician documents the episode and the intervention that provoked it.

A strip's R-R intervals range from 0.68 second to 1.12 second. A technician measures one pair of R waves, counts four large boxes, and charts a rate of 75 beats per minute. Why is that number unreliable?

• a.The 300 method may be used only when the first R wave falls on a heavy line
• b.The 300 method assumes all R-R intervals match the pair measured, which they do not✓
• c.The 300 method works only on strips that run longer than six seconds
• d.The 300 method cannot be used when the QRS complexes are narrow

Dividing 300 by the large boxes between two R waves converts one cycle length into a rate, which describes the whole strip only if every cycle is the same length. Here the intervals run from 0.68 to 1.12 second, so the measured pair yields 75 while other pairs would yield about 88 and about 54. On an irregular rhythm the technician counts the complexes in a six-second strip and multiplies by ten, which averages the variation. Starting on a heavy line is a convenience of the sequence method rather than a requirement of the 300 method, and neither strip length nor QRS width restricts it.

Why is a measured QT interval corrected for heart rate before it is compared with a normal limit?

• a.Because the QT interval lengthens as the heart rate rises
• b.Because paper speed changes the measured QT at fast rates
• c.Because T wave height varies with electrode position
• d.Because the QT interval shortens as the rate rises✓

Repolarization takes less time when the heart beats faster, so the raw QT shortens as the rate rises and lengthens as it falls, and a single normal range cannot fit both. Correction, most often by dividing the QT by the square root of the R-R interval in seconds, restates the value as the QT that rate would produce at 60 beats per minute, where the upper limits are about 0.44 second for men and about 0.46 second for women. The relationship runs the opposite way from the answer that has the QT lengthening with rate. Paper speed changes how wide the interval looks but not how many seconds it lasts, and T wave amplitude is not part of the measurement.

A febrile adult on telemetry has a regular narrow-complex rhythm at 148 beats per minute. A small upright deflection distorts the front of each T wave, and the rate has climbed gradually from 110 over the past hour. What is the most likely rhythm?

• a.Paroxysmal supraventricular tachycardia, a reentrant rhythm
• b.Atrial flutter with two-to-one AV conduction
• c.An accelerated rhythm from the AV junction
• d.Sinus tachycardia arising in the sinoatrial node✓

A rate that climbs gradually over an hour, with one upright atrial wave for every QRS partly buried in the preceding T wave, is sinus tachycardia; the sinus node speeds up and slows down over minutes rather than switching on and off. Paroxysmal supraventricular tachycardia starts and stops abruptly and usually parks at a fixed rate without visible atrial waves. Atrial flutter is the serious alternative here, but 2:1 conduction from an atrial rate near 300 holds the ventricular rate close to 150 whatever the patient's temperature, and it produces sawtooth waves best seen in leads II, III, and aVF, including a second atrial wave near the QRS. An accelerated junctional rhythm would run slower than this and would show an inverted P wave close to the QRS or none at all.

On a tracing recorded at 25 mm/sec, what is the normal upper limit for the width of the P wave, and in which lead is it usually assessed?

• a.0.12 second, or three small boxes, measured in lead II✓
• b.0.20 second, or one large box, measured in lead aVR
• c.0.08 second, or two small boxes, seen best in lead V6
• d.0.04 second, one small box, in any of the limb leads

A normal P wave is no wider than about 0.12 second, which is three small boxes at 25 mm/sec, and lead II is the conventional lead for judging it because the sinus P wave is upright and best formed there. The 0.20-second answer is the upper limit of the PR interval, not of the P wave itself, and aVR is the lead where a sinus P wave is inverted. Two small boxes would be 0.08 second, which is a common P wave duration but not the upper limit. One small box is 0.04 second, far narrower than a normal P wave.

A monitor strip shows regular sinus beats interrupted by one unexpected pause. The T wave immediately before the pause is taller and more pointed than every other T wave on the strip, and the sinus P waves resume on schedule after the pause. What most likely produced the pause?

• a.A second-degree AV block, type II, that dropped one conducted beat
• b.A sinus arrest in which the sinus node failed to fire
• c.An early atrial beat buried in the T wave that did not conduct✓
• d.A junctional escape beat that appeared before the next sinus beat

A deformed T wave just before an unexplained pause is the classic footprint of a nonconducted premature atrial contraction: the early P wave lands on the T wave and finds the AV node still refractory, so no QRS follows. Because the early P wave also resets the sinus node, the following P waves march out from the new timing, which fits the strip described. Second-degree type II block is ruled out by the extra deflection on the T wave, since in that block the P waves stay perfectly on time and no premature P wave appears. Sinus arrest would leave the baseline flat with no P wave at all during the pause, and an escape beat would fill the pause rather than create one.

A strip shows a regular narrow-complex rhythm at 190 beats per minute. Small P waves are visible in front of each QRS, but they are pointed and shaped differently from the same patient's sinus P waves recorded an hour earlier. Which rhythm best fits this tracing?

• a.Sinus tachycardia driven by fever, pain, or exertion
• b.Junctional tachycardia arising in the AV node
• c.Atrial flutter conducting two waves per QRS
• d.Atrial tachycardia from an ectopic atrial focus✓

P waves that are present but shaped unlike the patient's own sinus P waves point to an atrial focus outside the sinus node, and atrial tachycardia typically runs about 150 to 250 beats per minute, which brackets this rate. Sinus tachycardia would carry P waves identical in shape to the earlier baseline tracing. A junctional focus depolarizes the atria backward, so its P waves would be inverted in lead II or absent, not merely differently shaped. Atrial flutter conducting two atrial waves for each QRS would give a ventricular rate near 150, with sawtooth waves rather than discrete P waves.

A patient with severe emphysema has an irregular narrow-complex rhythm at 130 beats per minute. A P wave precedes every QRS, but at least three clearly different P wave shapes appear on the strip and the PR intervals vary along with them. What is this rhythm?

• a.Multifocal atrial tachycardia✓
• b.Coarse atrial fibrillation
• c.Wandering atrial pacemaker
• d.Atrial flutter with variable block

Three or more distinct P wave morphologies with varying PR intervals and a rate above 100 beats per minute define multifocal atrial tachycardia, which is strongly associated with chronic lung disease such as emphysema. Atrial fibrillation is excluded because organized P waves precede each QRS; coarse fibrillatory waves are not true P waves and do not carry measurable PR intervals. Wandering atrial pacemaker has the same shifting P wave pattern but by definition runs at 100 beats per minute or slower, so the rate of 130 rules it out. Atrial flutter would show identical sawtooth waves at roughly 250 to 350 per minute rather than several different P wave shapes.

A strip shows a slightly irregular rhythm at 78 beats per minute in which the P waves change shape from beat to beat, showing at least three different forms, and the PR intervals vary with them. What is this rhythm?

• a.Multifocal atrial tachycardia
• b.Wandering atrial pacemaker✓
• c.Atrial fibrillation, fine type
• d.Sinus arrhythmia with ectopy

Shifting P wave shapes with varying PR intervals at a rate of 100 beats per minute or slower is wandering atrial pacemaker, in which the dominant pacemaker site drifts among the sinus node, other atrial sites, and the AV junction. The rate is the only feature separating it from multifocal atrial tachycardia, which shows the identical pattern faster than 100 beats per minute; at 78 the slower label applies. Fine atrial fibrillation would have no organized P waves at all and no measurable PR interval. Sinus arrhythmia varies in rate with respiration but keeps one consistent P wave shape and a constant PR interval.

A regular narrow-complex rhythm at 150 beats per minute could be sinus tachycardia or atrial flutter conducting two atrial waves for each QRS. Which finding on the strip best separates the two?

• a.A ventricular rate that stays perfectly regular
• b.Narrow QRS complexes across the whole strip
• c.An upright deflection right before every QRS complex
• d.A second atrial wave hidden in each T wave✓

At an atrial rate near 300 per minute with two-to-one conduction, one flutter wave falls on the T wave of the preceding beat, so finding that extra buried deflection is the finding that identifies flutter; lead II and V1 usually show it best. A perfectly regular ventricular rate does not help, because sinus tachycardia and flutter with a fixed conduction ratio are both regular. Narrow QRS complexes only establish that the rhythm is supraventricular, which is true of both. An upright deflection before each QRS is the weakest discriminator of all, since a flutter wave arriving just ahead of the QRS is routinely mistaken for a sinus P wave.

In typical atrial flutter, what is the usual range of the atrial rate?

• a.Roughly 100 to 150 beats per minute
• b.Roughly 175 to 240 beats per minute
• c.About 250 to 350 beats per minute✓
• d.More than 400 beats per minute at rest

Typical atrial flutter arises from a reentry circuit in the right atrium that turns at about 250 to 350 atrial cycles per minute, most often near 300, producing the sawtooth flutter waves. The ventricular rate is much slower because the AV node blocks most of those impulses, which is why a flutter patient may show a pulse of 150, 100, or 75. A rate of 100 to 150 describes the ventricular response in flutter rather than the atrial rate itself, and 175 to 240 is closer to the range quoted for atrial tachycardia. Rates faster than 400 belong to atrial fibrillation, whose fibrillatory waves are chaotic and never form an organized sawtooth.

A strip shows uniform sawtooth atrial waves marching out regularly at about 300 per minute, but the R-R intervals are irregular and the ventricular rate wanders between 75 and 150 beats per minute. How should this rhythm be identified?

• a.Atrial fibrillation with a rapid ventricular response
• b.Atrial flutter conducting at a changing ratio at the AV node✓
• c.Multifocal atrial tachycardia with changing P wave shapes
• d.Sinus rhythm with frequent nonconducted atrial ectopy

Regular, identical sawtooth waves at about 300 per minute establish atrial flutter; when the AV node lets through a different number of those waves from beat to beat, the ventricular response becomes irregular, which is called flutter with variable conduction. Atrial fibrillation is the common misread here because the R-R intervals are irregular, but fibrillation has a chaotic baseline with no two atrial waves alike, whereas these waves are uniform and regular. Multifocal atrial tachycardia requires three or more different P wave shapes, not one repeating sawtooth. Frequent nonconducted atrial ectopy would show premature P waves of varying shape interrupting an otherwise sinus rhythm, not a continuous sawtooth baseline.

On a routine telemetry round a technician sees that a comfortable, stable patient whose rhythm was sinus earlier in the shift now has an irregularly irregular narrow-complex rhythm at 96 beats per minute with no identifiable P waves. What should the technician do?

• a.Tell the patient he has developed atrial fibrillation
• b.Notify the supervisor and save the strip✓
• c.Wait until the end of the shift to log the change
• d.Take the electrodes off and reapply them in an hour

A new irregularly irregular rhythm without P waves is a change in the patient's condition, and the technician's role is to recognize it, preserve the documentation, and pass it up promptly so a licensed clinician can evaluate it. Waiting until the end of the shift delays care for a rhythm change that may need same-day treatment, even though the rate is controlled and the patient feels well. Telling the patient his rhythm is atrial fibrillation is interpreting for the patient, which is outside the technician's scope. Removing and reapplying the electrodes discards the tracing that documents the change, and the finding here is a genuine rhythm, not an artifact pattern.

A patient watching the bedside monitor asks the technician what his irregular rhythm means and whether it is dangerous. What is the technician's most appropriate response?

• a.Explain that the rhythm is atrial fibrillation but is not serious
• b.Point out the missing P waves on the screen for the patient
• c.Say the tracing looks normal so the patient will not worry
• d.Refer the question to the nurse or the supervisor✓

A certified EKG technician acquires and monitors tracings and reports findings to licensed staff, but does not diagnose or interpret a rhythm for the patient, so the question belongs to the nurse or provider caring for him. Naming the rhythm as atrial fibrillation and calling it not serious is both a diagnosis and a prognosis, two things outside the technician's scope. Walking the patient through the missing P waves is interpretation in everything but name. Telling him the tracing looks normal is false reassurance and puts a false statement into the encounter.

A telemetry patient's rhythm changes to atrial fibrillation at 168 beats per minute, and the patient becomes pale and sweaty and says his chest feels tight. What should the technician do first?

• a.Report the rhythm change to the supervisor at the end of the round
• b.Print the strip and file it in the patient's chart
• c.Reposition the chest electrodes to confirm the rhythm
• d.Bring the nurse to the bedside now and stay with the patient✓

A rapid ventricular response with pallor, sweating, and chest tightness is a symptomatic rhythm change, and the technician's first duty is to get licensed help to the bedside immediately and keep the patient under observation. Finishing the round and reporting later is the wrong pace for a patient who is symptomatic right now, even though routine rhythm changes are handled that way. Printing and filing the strip is necessary documentation but does not bring anyone to the patient. Repositioning electrodes to confirm the rhythm wastes time and would be reasonable only if the tracing suggested artifact, which pallor, sweating, and chest tightness do not.

An early narrow beat with an abnormally shaped P wave is followed by a pause. The technician measures from the sinus beat before the early beat to the sinus beat after it and finds that distance is shorter than two normal R-R intervals. What does that measurement indicate?

• a.The early beat reset the sinus node, so the pause is noncompensatory✓
• b.The early beat started in the ventricles and gave a full compensatory pause
• c.The sinus node failed to fire for one full cycle, producing a sinus arrest
• d.The AV node blocked one sinus impulse, so a whole beat was dropped

A premature atrial contraction usually depolarizes the sinus node early and restarts its timing cycle, so the sinus beat after the ectopic arrives sooner than expected and the pause is called noncompensatory. Measured across the early beat, that shortfall is exactly what a distance of less than two normal R-R intervals shows. A premature ventricular contraction typically leaves the sinus node undisturbed, so its pause is fully compensatory and the same measurement equals two R-R intervals; the narrow QRS and the visible early P wave also place this beat above the ventricles. Sinus arrest and a dropped conducted beat both leave a pause without any premature beat in front of it, and here an early beat clearly precedes the pause.

In an otherwise sinus rhythm the monitor shows a pause of about 1.6 seconds, which is ended by a single narrow beat carrying an inverted P wave immediately after its QRS. How should the technician label this beat?

• a.A junctional escape beat✓
• b.A premature junctional contraction
• c.A nonconducted atrial beat
• d.A ventricular escape beat

A beat that ends a pause has arrived late, and timing is what separates an escape beat from a premature one: the escape beat appears only after the higher pacemaker has failed to deliver on time, making it a protective backup rather than an irritable focus. The inverted P wave following a narrow QRS places the origin in the AV junction, so this late beat is a junctional escape beat. A premature junctional contraction looks similar in shape but comes early, interrupting the underlying rhythm instead of rescuing it. A ventricular escape beat would be wide and bizarre because it bypasses the normal conduction pathway, and a nonconducted atrial beat produces no QRS at all.

A technician reads a report describing a patient's rhythm as supraventricular. What does that term indicate about the origin of the impulse?

• a.It started in the Purkinje fibers of the ventricular walls
• b.It started above the ventricles, in the atria or junction✓
• c.It started above the AV node, in the atria or sinus node
• d.It started in the left bundle branch and spread down

Supraventricular means the impulse formed anywhere above the ventricles, which includes the sinus node, any atrial focus, and the AV junction itself. Because such an impulse still reaches the ventricles through the normal His-Purkinje pathway, it depolarizes them quickly and produces a narrow QRS of less than 0.12 second, which is why a narrow QRS points above the ventricles. Restricting the term to sites above the AV node is the common error, since junctional rhythms are supraventricular too, which is why junctional tachycardia belongs to the supraventricular family. The Purkinje fibers and the bundle branches lie inside the ventricular conduction system, so a beat starting there spreads partly through muscle and widens the QRS.

A monitor shows a regular wide-complex tachycardia at 165 beats per minute in a patient who has a pulse. The rhythm could be ventricular tachycardia or a supraventricular tachycardia conducted with aberrancy. What is the safest working assumption while licensed staff evaluate the patient?

• a.Assume aberrant conduction because the rate is under 180
• b.Assume the rhythm is benign while a pulse is present
• c.Regard the rhythm as ventricular tachycardia✓
• d.Assume atrial flutter conducting one wave per QRS

The standard teaching for any wide-complex tachycardia of uncertain origin is to regard it as ventricular tachycardia until a qualified clinician proves otherwise, because that assumption is the one that fails safely. Rate does not distinguish the two, since ventricular tachycardia and supraventricular tachycardia with aberrancy overlap heavily in the range around 165. The presence of a pulse says only that the rhythm is perfusing at this moment; ventricular tachycardia commonly has a pulse before it deteriorates. Assuming flutter conducting one atrial wave per QRS is a guess the technician cannot support and would set the urgency far too low.

A junctional rhythm is labeled junctional tachycardia rather than accelerated junctional rhythm once the rate exceeds what value?

• a.Faster than 60 beats per minute
• b.Faster than 100 beats per minute✓
• c.Faster than 140 beats per minute in adults
• d.Faster than 120 beats per minute at rest

Junctional rhythms are named by how far the junctional focus has been driven above its inherent 40 to 60 beats per minute: 60 to 100 is an accelerated junctional rhythm, and above 100 the rhythm is called junctional tachycardia. Passing 60 marks the boundary between junctional escape rhythm and accelerated junctional rhythm, not the tachycardia threshold. The figures of 120 and 140 are simply higher rates within junctional tachycardia and do not mark any naming boundary. The morphology stays the same across all three labels, with a narrow QRS and an inverted or absent P wave, so the rate is what determines the name.

A strip shows a regular narrow-complex rhythm at 82 beats per minute. Lead II shows no upright P waves; instead a small inverted deflection sits just ahead of each QRS with a PR interval of 0.08 second. How should this rhythm be identified?

• a.Sinus rhythm, since a P wave precedes each QRS
• b.Junctional escape rhythm, the junction's inherent rate
• c.Accelerated junctional rhythm from the AV junction✓
• d.Junctional tachycardia from an irritable focus

An inverted P wave in lead II with a PR interval shorter than 0.12 second marks a junctional origin, and a sustained junctional rhythm at 82 beats per minute sits in the 60 to 100 window that defines an accelerated junctional rhythm. A junctional escape rhythm would run at the junction's inherent 40 to 60 beats per minute, so 82 is too fast for that label. Junctional tachycardia requires a rate above 100, so 82 is too slow for it. Sinus rhythm is excluded because a sinus impulse depolarizes the atria downward and produces an upright P wave in lead II with a PR interval of at least 0.12 second.

In a beat that originates in the AV junction, why does the P wave appear inverted in lead II?

• a.The sinus impulse travels to the atria through an accessory pathway
• b.The atria depolarize backward, away from the positive electrode✓
• c.The ventricles depolarize before the atria have finished
• d.The left leg electrode has been reversed with the right arm

Lead II looks from the right arm toward the left leg, so its positive electrode sits low on the left; a sinus impulse traveling downward toward that electrode writes an upright P wave. A junctional impulse instead spreads retrograde, upward from the junction into the atria and away from the positive electrode of lead II, which inverts the P wave. Whether that inverted P wave lands before the QRS, inside it, or after it depends only on how fast the impulse reaches the atria relative to the ventricles, not on the direction. Timing is also why saying the ventricles fire before the atria explains a P wave that follows the QRS but not the inversion itself, and a limb lead reversal would distort several leads at once rather than produce this consistent junctional pattern.

While recording a routine 12-lead, a technician notices several early beats whose P waves are shaped differently from the sinus P waves and which are followed by narrow QRS complexes. The patient is comfortable and has no complaints. What should the technician do?

• a.Stop the recording and notify the supervisor before continuing
• b.Finish the 12-lead and note the early beats on it✓
• c.Repeat the tracing until a strip with no early beats prints
• d.Delete the tracing and record it after the beats settle down

Early beats with an abnormal P wave and a narrow QRS are premature atrial contractions, which are common, are frequently seen in healthy people, and are not an emergency in a comfortable patient; the technician completes the tracing and notes the ectopy so the interpreting clinician sees it. Stopping a routine tracing on a stable patient to escalate delays the study without changing anything about the patient's care. Repeating the tracing until no early beats appear discards real diagnostic information, which is the opposite of what the recording is for. Deleting the tracing destroys documentation of a finding the provider should see.

Two strips both show atrial fibrillation. On the first, the baseline between QRS complexes carries tall, easily seen fibrillatory waves; on the second the baseline is nearly flat with only a slight ragged quiver. How are these two tracings described?

• a.The first is atrial flutter and the second is fibrillation
• b.The first has a faster ventricular rate than the second
• c.The first is coarse and the second is fine atrial fibrillation✓
• d.The first is untreated and the second has been converted

Fibrillatory waves are described by their amplitude: prominent, easily visible waves are called coarse atrial fibrillation, and a nearly flat, barely undulating baseline is called fine atrial fibrillation. Both remain atrial fibrillation, and both show the same defining features of absent P waves and irregularly irregular R-R intervals. Wave amplitude does not set the ventricular rate, which depends on how many impulses the AV node conducts, so either pattern can appear with a fast or a controlled rate. Neither pattern is flutter, whose waves are uniform and organized into a sawtooth, and a converted patient would be back in an organized rhythm with real P waves rather than a quivering baseline.

Atrial fibrillation is described as having a rapid ventricular response when the ventricular rate rises above what value?

• a.Above 100 beats per minute✓
• b.Above 120 beats per minute in adults
• c.Above 150 beats per minute at rest
• d.Above 80 beats per minute when awake

The ventricular rate in atrial fibrillation is judged against the ordinary adult range, so a rate over 100 beats per minute is a rapid ventricular response and a rate under 100 is described as controlled. The threshold has nothing to do with symptoms, which is why a patient at 110 with no complaints is still charted as having a rapid ventricular response. The figures of 120 and 150 are faster rates that certainly qualify but are not the boundary, and using them would mislabel a patient at 110 as controlled. A rate above 80 is within the normal adult range and would not be called rapid in any patient.

Why is atrial fibrillation associated with an increased risk of stroke?

• a.The fast ventricular rate injures the lining of the coronary arteries
• b.The atria quiver rather than contract, so blood pools and clots✓
• c.The irregular rhythm raises blood pressure inside the skull
• d.Clots form in the ventricles because they fill irregularly

In atrial fibrillation the atrial muscle quivers instead of contracting as a unit, so the atria do not empty completely; blood stagnates, particularly in the left atrial appendage, and can form a clot that later travels to the brain. That loss of coordinated atrial contraction is also why cardiac output falls even when the ventricular rate is controlled. The stagnation is atrial rather than ventricular, since the ventricles still contract fully with every beat and eject their contents even though the intervals between beats are uneven. Coronary artery injury describes atherosclerotic disease rather than anything fibrillation does to a vessel wall, and pressure inside the skull has no relationship to the atrial rhythm.

An early beat on a sinus strip has a wide, unusual QRS. Close inspection shows a premature P wave distorting the T wave of the preceding beat, and the pause after the early beat is not fully compensatory. How is this beat best classified?

• a.A premature ventricular contraction with a retrograde P wave
• b.A ventricular escape beat arriving after a dropped sinus beat
• c.A premature atrial beat conducted aberrantly down a bundle branch✓
• d.A fusion beat formed by two impulses meeting in the ventricle

The premature P wave riding on the preceding T wave shows the impulse began in the atria, and the noncompensatory pause confirms that the ectopic reset the sinus node, both of which mark an atrial origin. The QRS is wide only because the early impulse reached a bundle branch that had not yet recovered, so it conducted with aberrancy; a supraventricular beat with aberrancy is the classic imitator of a ventricular beat. A premature ventricular contraction would have no P wave in front of it and would usually leave a full compensatory pause. An escape beat comes late rather than early, and a fusion beat requires a ventricular impulse and a supraventricular impulse to reach the ventricles at the same moment, producing a hybrid shape rather than the sequence described.

Telemetry captures a regular narrow-complex tachycardia at 130 beats per minute that speeds up gradually over several beats, with inverted P waves following each QRS. Which rhythm best fits this tracing?

• a.Junctional tachycardia from a fast junctional focus✓
• b.Paroxysmal supraventricular tachycardia with a sudden onset
• c.Atrial tachycardia from an ectopic focus high in the atrium
• d.Accelerated junctional rhythm that has sped up a little

Inverted P waves after each QRS place the pacemaker in the AV junction, and a junctional rate above 100 beats per minute is junctional tachycardia; its onset is characteristically gradual, warming up over several beats. Paroxysmal supraventricular tachycardia is the close call here because it is also narrow and regular, but it begins and ends abruptly, often from one beat to the next, and its rate usually runs higher than 130. An accelerated junctional rhythm has the same P wave pattern and the same gradual onset but is defined as 60 to 100 beats per minute, so 130 is above its ceiling. Atrial tachycardia would show upright ectopic P waves ahead of the QRS rather than inverted ones behind it.

A telemetry monitor records a narrow-complex tachycardia at 200 beats per minute that starts abruptly, runs for 40 seconds, and stops on its own. The patient felt a flutter in his chest and is now comfortable. What should the technician do with the tracing?

• a.Print the strip and record the times the fast rhythm began and ended✓
• b.Discard the strip, since the rhythm corrected itself and the patient is well
• c.Silence the alarm and reset the monitor so the same episode is not recounted
• d.Wait for a second episode before printing anything from the monitor

A self-terminating run of a paroxysmal supraventricular tachycardia is exactly the evidence a provider needs, and it exists only if the technician preserves it; the printed strip plus the onset and termination times documents how fast the rhythm ran and how long it lasted. The abrupt start and stop are themselves diagnostic features worth capturing on paper. Discarding the strip because the patient feels well erases the only record of the episode, and the fact that a rhythm self-terminated does not make it unimportant. Silencing the alarm and resetting the monitor addresses the noise rather than the finding, and waiting for a second episode gambles that another one will occur while the patient is still monitored.

A strip shows uniform sawtooth atrial waves at 300 per minute with one QRS complex after every third sawtooth wave. What is the ventricular rate, and how is the conduction described?

• a.About 75 beats per minute, four-to-one conduction
• b.About 150 beats per minute, two-to-one block
• c.About 300 beats per minute, one-to-one block
• d.About 100 beats per minute, three-to-one conduction✓

Dividing the atrial rate by the conduction ratio gives the ventricular rate, so 300 divided by 3 is 100 beats per minute, described as atrial flutter with three-to-one conduction. Two-to-one conduction from the same atrial rate would yield 300 divided by 2, or 150, and four-to-one would yield 300 divided by 4, or 75; both are common flutter presentations but neither matches a QRS after every third wave. One-to-one conduction would drive the ventricles at 300, which the AV node rarely permits and which would be a medical emergency. Counting the sawtooth waves between QRS complexes is the reliable way to establish the ratio.

A six-second strip recorded in one lead contains five premature wide beats, and those beats have two clearly different shapes. What does the difference in shape indicate?

• a.The premature beats are unifocal and come from a single site
• b.The premature beats are fusion beats formed in the AV junction
• c.The premature beats are multifocal and come from separate sites✓
• d.The premature beats are supraventricular beats conducted aberrantly

Premature ventricular complexes that arise from different ventricular sites depolarize the ventricles along different paths, so their QRS shapes differ within the same lead; identical shapes in one lead describe unifocal ectopy. Multifocal ectopy is reported promptly because it points to more widespread ventricular irritability. A fusion beat is a single hybrid complex created when a supraventricular impulse and a ventricular impulse activate the ventricles at the same time, not a set of beats with two repeating shapes. Supraventricular beats conducted aberrantly are preceded by a premature P wave, which these beats lack.

An otherwise sinus strip contains two wide, bizarre complexes occurring back to back, arriving earlier than the next expected sinus beat, and neither one is preceded by a P wave. What is this pattern called?

• a.A ventricular triplet, also described as a short salvo
• b.A short run of nonsustained ventricular tachycardia
• c.A pair of ventricular escape beats from the Purkinje fibers
• d.A ventricular couplet, which may be uniform or multiform✓

Two premature ventricular complexes in a row are a couplet; three in a row are a triplet or salvo, and three or more consecutive ventricular beats at a rate above 100 beats per minute are commonly reported as a run of ventricular tachycardia. Counting the consecutive ectopic beats is what separates these terms. Escape beats are late rather than early: they appear after a pause when the higher pacemakers fail, while these complexes interrupt the underlying rhythm ahead of the next expected beat. The two complexes may look alike or differ in shape, and either way the technician documents the pattern and its frequency and leaves the significance to the provider.

A patient with a permanent pacemaker is on telemetry. Sharp pacing spikes appear at a regular rate of 60, but many of the spikes are followed by no QRS complex at all, and the patient's own rate is 42 beats per minute. What is this malfunction called, and what should the technician do?

• a.Failure to capture; notify the supervisor and save the strip✓
• b.Undersensing of intrinsic beats; notify the supervisor and save the strip
• c.Pacemaker oversensing; notify the supervisor and save the strip
• d.Loss of pacer output; notify the supervisor and save the strip

A pacing spike that produces no complex is failure to capture: the generator delivers its impulse on schedule, but the impulse does not depolarize the myocardium, so the patient is left with an underlying rate of 42 beats per minute. Undersensing is the opposite fault, in which the generator does not recognize the patient's own beats and fires into them, sometimes onto a T wave. Oversensing is the generator mistaking other signals, such as muscle activity, for intrinsic beats and withholding pacing that it should have delivered. Loss of output means no spikes reach the tracing at all, while here the spikes are present and regular. Naming the malfunction does not change what the technician does, since reporting it promptly and keeping the tracing is the response to any of them; adjusting the device belongs to the provider or the device clinic.

During continuous monitoring, a strip shows a nine-beat run of regular wide complexes at 180 beats per minute that stops on its own. The patient is awake and reports that she felt lightheaded during the run. What should the technician do?

• a.Report the run to the supervisor immediately and save the labeled strip✓
• b.Wait for a second run before mentioning the episode to the care team
• c.Delete the section as artifact, since the rhythm corrected by itself
• d.Chart the run at the end of the shift because it needed no treatment

A run of wide complexes at 180 beats per minute that ends on its own is nonsustained ventricular tachycardia, and symptoms during the run make it a finding the care team needs while the strip is still available. The technician's job is to recognize, report, and preserve the tracing, not to decide whether the run matters. Waiting for a recurrence or charting at the end of the shift delays information that may change monitoring or treatment within minutes. The run is not artifact: artifact does not produce uniform complexes at a steady rate, and the patient's symptoms fit the tracing.

Two strips both show chaotic, irregular waveforms with no identifiable QRS complexes. On the first the deflections are tall and coarse; on the second they are low and fine. What does the difference between the two tracings most likely reflect?

• a.The fine tracing indicates a slower ventricular rate than the coarse one
• b.The coarse tracing is muscle artifact and the fine tracing is true arrest
• c.The fine tracing means an electrode has loosened and weakened the signal
• d.Fibrillation has usually been present longer when the waves are fine✓

Coarse ventricular fibrillation, with taller deflections, is typically seen soon after onset, while the waveform becomes fine as the myocardium is deprived of oxygen and its energy stores fall, so fine fibrillation usually means more time has passed. Both are pulseless, both are handled as cardiac arrest, and the technician's response does not change with the amplitude. Rate cannot be measured in fibrillation because there are no organized complexes to measure between. A loose electrode produces a wandering or flat baseline rather than continuous chaotic deflections, and muscle artifact leaves recognizable QRS complexes marching through it.

A patient who is unresponsive and has no palpable pulse shows occasional wide, misshapen complexes at about 8 beats per minute on the monitor, with no P waves. How is this tracing best described?

• a.Fine ventricular fibrillation with a few conducted wide beats
• b.An agonal rhythm that slows progressively toward asystole✓
• c.An accelerated idioventricular rhythm near its lowest rate
• d.A complete heart block with a ventricular escape focus

An agonal rhythm shows a few widely spaced, wide and irregular complexes, usually well under 20 beats per minute, with no pulse; it is handled as cardiac arrest rather than as a perfusing rhythm, and it commonly deteriorates into asystole. Ventricular fibrillation has no discrete complexes at all, only a chaotic baseline, so recognizable complexes rule it out. An accelerated idioventricular rhythm runs between 40 and 100 beats per minute, far faster than this tracing. Complete heart block requires visible P waves marching at their own rate, and none are present here.

A monitor displays an organized rhythm at 70 beats per minute with narrow QRS complexes and upright P waves, but the patient is unresponsive and no pulse can be felt. How is this situation described?

• a.Ventricular tachycardia hidden by the monitor's filter setting
• b.Sinus rhythm with a broken cable between patient and monitor
• c.Artifact created by the chest compressions that are being delivered
• d.Pulseless electrical activity, which is managed as cardiac arrest✓

Pulseless electrical activity is organized electrical activity on the monitor without a mechanical pulse; the tracing shows depolarization, not the ejection of blood, which is why the patient rather than the monitor decides what is happening. The finding is treated as cardiac arrest, and the technician calls for help immediately and stays with the patient. A cable fault or filter problem would distort or lose the tracing, not produce clean narrow complexes with P waves in an unresponsive patient. Compression artifact appears as broad regular waves at the compression rate superimposed on the baseline, and compressions have not been started here.

A strip shows a regular rhythm at 65 beats per minute with wide QRS complexes, no P waves, and T waves pointing opposite to the QRS complexes. What is this rhythm?

• a.An accelerated idioventricular rhythm✓
• b.Slow monomorphic ventricular tachycardia
• c.An idioventricular escape rhythm
• d.A junctional rhythm with bundle branch block

A ventricular focus firing faster than its inherent 20 to 40 beats per minute but slower than 100 produces an accelerated idioventricular rhythm, and 65 beats per minute falls squarely in that 40 to 100 range. Ventricular tachycardia is used for ventricular rhythms above 100 beats per minute, so the rate here excludes it. An idioventricular escape rhythm runs at that inherent 20 to 40 beats per minute, well below this rate. A junctional rhythm carrying a bundle branch block is the closest competing answer, since it also produces wide complexes, but the junctional inherent rate is 40 to 60 beats per minute and inverted P waves are often visible just before or just after the QRS complexes.

A telemetry monitor alarms for asystole. The first displayed lead shows a flat line, the second displayed lead shows a normal rhythm at 76 beats per minute, and the patient is sitting up talking with a visitor. What should the technician do first?

• a.Silence the alarm and note that the asystole limit is set too high
• b.Check the electrode and lead wire for the flat lead and replace them✓
• c.Report the asystole to the supervisor before touching any of the leads
• d.Print a strip from the flat lead and place it in the patient's record

A flat line in one lead while another lead shows an organized rhythm in a patient who is awake and talking is a lead problem: a dried, loose, or disconnected electrode, or a broken lead wire. True asystole is confirmed in two or more leads in a patient who is unresponsive and pulseless, and neither condition is met here. Escalating a rhythm the patient plainly is not in wastes time when the fix is at the electrode, and silencing the alarm without repairing the lead leaves the monitor unable to detect a real event. Filing a tracing of an artifact documents the wrong thing.

Within each group of conducted beats in a second-degree AV block, type I, what happens to the R-R intervals as the group progresses toward the dropped beat?

• a.They stay exactly equal, because only the PR interval is changing
• b.They shorten slightly with each successive beat✓
• c.They lengthen from beat to beat as each PR interval lengthens
• d.They vary at random, with no repeating pattern across the group

In type I block the PR interval lengthens by a smaller amount with each successive beat, so each R-R interval is slightly shorter than the one before it until a P wave is not conducted. The pause that contains the dropped beat is less than twice the shortest R-R interval in the group, which is the other classic clue. Assuming the R-R must lengthen because the PR lengthens is the usual error and reverses the actual pattern. The rhythm is not random: the repeating cluster of beats followed by a pause is the grouped beating that makes the block recognizable at a glance.

A patient with a demand ventricular pacemaker has an underlying rhythm at 68 beats per minute. Pacing spikes appear without regard to the patient's own beats, and one spike lands on a T wave. What should the technician do?

• a.Document normal demand pacing and continue routine monitoring
• b.Print the strip, note the spikes, and pass it along at the end of the shift
• c.Notify the supervisor promptly and save the tracing that was recorded✓
• d.Reposition the patient, since the spikes are movement artifact

A demand pacemaker is supposed to sense the patient's own beats and withhold its output; spikes that ignore intrinsic beats are failure to sense, and a spike landing on a T wave falls in the vulnerable period and can provoke ventricular tachycardia or fibrillation. That combination is reported without delay and the tracing is kept as evidence for the provider and the device clinic. Printing the strip and noting the spikes is proper work in itself, but holding the finding until the shift ends delays a report on a malfunction that can cause an arrest in the meantime. Calling it normal demand pacing misses that the generator is competing with the patient's own rhythm, and pacer spikes are sharp and evenly sized within a lead, unlike the irregular deflections of movement artifact.

A strip shows exactly two P waves for every QRS complex throughout, and the PR interval of every conducted beat measures 0.24 second. How should the technician describe this rhythm?

• a.Second-degree AV block, type II, from the constant PR interval
• b.Second-degree AV block, type I, because a P wave is regularly dropped
• c.Complete heart block, because two P waves appear for each QRS complex
• d.Second-degree AV block with 2:1 conduction, type not classified✓

With 2:1 conduction there are never two conducted beats in a row, so there is no sequence of PR intervals in which lengthening could be seen, and the strip cannot be sorted into type I or type II from the ratio alone; it is reported as 2:1 AV block. A constant PR interval does not settle the question, because in 2:1 conduction every conducted beat is the first beat of its group and would have the same PR in either type. Regularly dropped P waves occur in both types and do not identify type I. Complete heart block is excluded because the conducted P waves hold a fixed relationship to the QRS complexes.

Compared with a second-degree AV block, type I, why is a second-degree AV block, type II, generally treated as the more serious finding?

• a.Type II drops a larger share of the P waves in most patients
• b.Type II is the only second-degree block that leaves a pause
• c.Type II lies below the AV node and may progress to complete block✓
• d.Type II responds to atropine, while type I usually does not respond

Type I block is usually located within the AV node and is often transient, while type II usually arises in the His-Purkinje system below the node, frequently shows a wide QRS, and can progress without warning to complete heart block, which is why it is reported promptly. The number of dropped beats does not determine the type; a type I block can drop as many beats as a type II block. Both types produce pauses on the strip, so a pause identifies neither. The atropine claim is reversed as well as outside the technician's scope, since atropine acts on the AV node and is the nodal block that may respond.

A monitored patient's QRS complexes measure 0.14 second. What is it about a bundle branch block that widens the QRS complex?

• a.The atria and the ventricles depolarize together through the AV node
• b.One ventricle depolarizes late because the impulse spreads muscle to muscle✓
• c.The impulse turns back through the AV node and depolarizes the atria
• d.The ventricles repolarize more slowly, which stretches the QRS complex

When one bundle branch is blocked, the ventricle it serves is not activated through the fast Purkinje network; the impulse reaches it by slower cell-to-cell spread from the other ventricle, so the two ventricles depolarize one after the other instead of together and the QRS reaches 0.12 second or more. Repolarization of the ventricles is represented by the T wave, so slowing it would not widen the QRS. Conduction turning back toward the atria produces an inverted P wave near the QRS, as in junctional beats, rather than a wide complex. Simultaneous atrial and ventricular depolarization is not what normal conduction does at all.

A technician records a single-lead rhythm strip that shows wide QRS complexes with an rSR' pattern. What is the appropriate way to report this finding?

• a.As a right bundle branch block, which the rSR' pattern shows
• b.As wide QRS complexes, noting that a 12-lead is needed to say more✓
• c.As a left bundle branch block, since the QRS exceeds 0.12 second
• d.As ventricular beats, since the complexes are wide and misshapen

An rSR' pattern is associated with right bundle branch block, but naming the side depends on the QRS shape in V1 and V6 on a 12-lead, and a monitoring lead is not V1 unless it was deliberately set up as a modified chest lead. The technician measures and describes what is on the strip, including QRS duration and morphology, and leaves the interpretation to the provider. Width alone identifies neither branch, since both blocks widen the QRS past 0.12 second. Wide complexes that follow P waves with a consistent PR interval are conducted beats rather than ventricular ectopic beats.

A patient with a demand pacemaker programmed to 60 beats per minute is on telemetry. The strip shows long pauses with no pacing spikes at all during them, and each pause follows a burst of muscle noise on the baseline. What is the most likely explanation?

• a.Oversensing, in which noise is read as beats and output is withheld✓
• b.Failure to capture, since the paced impulses produce no complexes
• c.Failure to sense, since the generator fires without regard to the beats
• d.Battery depletion, to be reported to the supervisor as a failed device

A demand pacemaker withholds its output whenever it senses electrical activity, so when it counts muscle tremor or other electrical noise as ventricular beats it stops pacing and the rate falls below the programmed 60 beats per minute; the pauses tracking the noise bursts are the giveaway. Failure to capture shows spikes that produce no complex, yet during these pauses there are no spikes at all. Failure to sense produces the opposite picture, extra spikes competing with the patient's own beats. Battery status is determined by device interrogation rather than from a rhythm strip, and declaring a device failed is not the technician's call.

A strip shows a regular wide-complex tachycardia at 160 beats per minute. Which additional finding on that strip would most support ventricular tachycardia rather than a supraventricular rhythm conducted with aberrancy?

• a.QRS complexes that measure more than 0.12 second across the strip
• b.T waves that point in the same direction as the QRS complexes
• c.P waves marching through at an unrelated rate of 80 per minute✓
• d.An R-R interval that stays regular from the first to the last beat

Independent P waves continuing at their own slower rate through the tachycardia show AV dissociation, which strongly favors a ventricular origin; capture beats and fusion beats point the same way. A QRS wider than 0.12 second is present in both possibilities, since aberrant conduction widens the complex too, so width alone separates nothing. Regularity is likewise shared by both. T waves in wide-complex beats usually point opposite the QRS, so concordant T waves are not a feature that favors either. Whatever the strip suggests, the technician reports a wide-complex tachycardia and gets help rather than naming the mechanism.

A monitored patient's rhythm changes to a ventricular rate of 34 beats per minute with wide QRS complexes and P waves bearing no relationship to them. The patient says he feels faint and looks pale. What should the technician do?

• a.Recheck the electrodes, since a rate that low is usually a lead problem
• b.Report the strip to the supervisor at the end of the current monitoring round
• c.Ask the patient to sit upright so his ventricular rate will come up
• d.Stay with the patient and alert the nurse at once, per facility policy✓

A new complete heart block at 34 beats per minute in a patient with symptoms is an emergency finding, so the technician stays with the patient, summons the nurse or the emergency response as facility policy directs, and keeps the strip running for the team. Holding the tracing until the end of the round delays care that is needed now. Clean, regular wide complexes with independent P waves are a real rhythm and not a lead problem, so troubleshooting electrodes first wastes time. Sitting a lightheaded patient upright does not restore conduction through a blocked pathway and adds a fall risk.

A sinus strip at 70 beats per minute contains one wide, bizarre beat sandwiched between two consecutive sinus beats, and the surrounding sinus P-P and R-R intervals are undisturbed. What is the wide beat called?

• a.A ventricular escape beat, since no pause follows it
• b.A fusion beat formed by two impulses meeting in the ventricle
• c.An interpolated premature ventricular contraction✓
• d.A junctional premature beat with aberration

An interpolated premature ventricular contraction falls between two normally timed sinus beats without resetting the sinus node, so no compensatory pause follows it and the underlying cycle continues undisturbed. A ventricular escape beat is late rather than early and appears after a pause when the higher pacemakers have failed, which does not fit a beat squeezed into an intact sinus cycle. A fusion beat is a single hybrid complex whose shape lies between that of a sinus beat and that of a ventricular beat. A junctional premature beat is narrow unless it is conducted aberrantly, comes early with an inverted P wave near the complex, and usually resets the underlying rhythm.

A strip shows a rapid wide-complex rhythm whose QRS complexes change amplitude gradually and appear to twist around the baseline. Which measurement from the same patient's earlier tracing is most closely related to this rhythm?

• a.A PR interval of 0.22 second measured on the earlier tracing
• b.A QRS duration of 0.10 second measured on the earlier tracing
• c.A corrected QT interval of 0.52 second measured on the earlier tracing✓
• d.An R-R interval that varied with breathing on the earlier tracing

The twisting pattern is torsades de pointes, a polymorphic ventricular tachycardia that arises when the QT interval is prolonged, and a corrected QT of 0.52 second is well beyond the usual upper limits of about 0.44 second in men and 0.46 second in women. A PR interval of 0.22 second is a first-degree AV block, a delay in conduction into the ventricles that does not set up this rhythm. A QRS of 0.10 second is within the normal range of less than 0.12 second. R-R intervals that vary with breathing describe sinus arrhythmia, a normal variant.

Leads I, II, and III are described as bipolar limb leads. What does the term bipolar describe about these three leads?

• a.Each records the difference in voltage between two limb electrodes, one acting as positive and one as negative✓
• b.Each records voltage at one positive electrode and compares it with a calculated zero reference point
• c.Each displays two separate waveforms at the same time, one taken from the arms and one from the legs
• d.Each can be recorded with either polarity, so the complexes may be printed upright or inverted

A bipolar lead has a true positive and a true negative electrode: lead I is left arm minus right arm, lead II is left leg minus right arm, and lead III is left leg minus left arm. The description of one positive electrode measured against a calculated zero reference belongs to the augmented leads aVR, aVL, and aVF, which are unipolar. No lead prints two waveforms at once, and polarity is fixed by the definition of the lead rather than chosen at the machine. The right leg electrode is a neutral reference and forms no part of any of the three bipolar leads.

On a normal 12-lead tracing, the P wave, QRS complex, and T wave are all negative in lead aVR. What accounts for this?

• a.Its positive electrode sits at the right shoulder, facing away from the path of depolarization✓
• b.The right arm electrode is the negative pole in leads I and II, so everything at aVR prints inverted
• c.The augmented leads are printed at reduced sensitivity, which pushes their deflections below the baseline
• d.It is the one lead that records repolarization only, and repolarization runs opposite to depolarization

The overall wave of depolarization in a normal heart travels down and to the left, toward the left leg and the left lower chest. The positive electrode of aVR sits at the right shoulder, so that wave moves away from it and writes negative deflections in every part of the complex. The right arm does serve as the negative pole in leads I and II, but that has no bearing on aVR, where the right arm carries the positive pole. Inversion in aVR alone is expected on a correctly recorded tracing, the augmented leads are printed at the same 10 mm/mV calibration as every other lead, and no lead records repolarization by itself.

A physician asks a technician which leads on the 12-lead tracing look at the inferior surface of the heart. Which answer is correct?

• a.Leads I and aVL, whose positive electrodes sit on the left arm side of the frontal plane
• b.Leads V1 and V2, whose positive electrodes sit on either side of the sternum
• c.Leads II, III, and aVF, whose positive electrodes all point downward toward the left leg and foot✓
• d.Leads V5 and V6, whose positive electrodes sit low on the left side of the chest wall

The inferior surface of the heart rests on the diaphragm, and the three leads whose positive poles point down toward the left leg record it: leads II, III, and aVF. Leads I and aVL point toward the left shoulder and record the high lateral wall, which is a frontal-plane group as well and is the most common wrong choice here. The pair beside the sternum records the septum, and the two low left chest leads record the low lateral wall. Grouping leads by the surface they face is what lets a technician describe where a change appears without interpreting it.

A tracing shows ST segment changes in leads I and aVL while V5 and V6 look unchanged. Which region do leads I and aVL view?

• a.The anterior wall of the left ventricle, the same region recorded by V3 and V4
• b.The high lateral wall, which lies above the region recorded by V5 and V6✓
• c.The inferior wall, the same region recorded by leads II, III, and aVF
• d.The septum between the ventricles, recorded also by V1 and V2

Leads I and aVL are frontal-plane leads whose positive poles face the left shoulder, so they record the high lateral portion of the left ventricle. The low lateral wall is recorded by V5 and V6, which is why changes can appear in the two limb leads while those chest leads stay normal. The anterior wall belongs to V3 and V4, the inferior wall to II, III, and aVF, and the septum to V1 and V2. A technician reports which leads show the change and leaves the interpretation to the physician.

A patient scheduled for a routine 12-lead EKG has documented dextrocardia. What is the correct way to record the tracing?

• a.Record the standard 12-lead with no change and let the interpreting physician allow for the reversed anatomy
• b.Report to your supervisor that a 12-lead cannot be recorded on a patient whose heart lies on the right
• c.Mirror the chest electrodes onto the right chest and reverse the two arm electrodes✓
• d.Leave the chest electrodes in the usual places and move only the limb electrodes to the right side of the body

With the heart lying on the right, the standard positions face away from the chambers, so the chest electrodes are mirrored across to the right chest and the arm electrodes are reversed to match the reversed anatomy. The tracing has to be clearly labeled as a dextrocardia recording, because an unlabeled mirrored tracing looks like arm lead reversal to whoever reads it. Recording an unmodified 12-lead produces a tracing that imitates limb lead reversal with poor R wave progression, which is exactly the confusion the modified placement avoids. Dextrocardia does not prevent a technician from obtaining a usable tracing, so escalating instead of recording delays the study for no reason.

A student asks a technician to explain the difference between an electrode and a lead. Which explanation is correct?

• a.An electrode is the wire running from the machine, and a lead is the adhesive patch stuck to the skin
• b.An electrode is the sensor on the skin, and a lead is the view of the heart made by comparing electrodes✓
• c.The two terms mean the same thing, since each electrode applied to the patient prints one lead
• d.An electrode picks up rhythm only, and a lead picks up both the rhythm and the size of the chambers

An electrode is the physical sensor stuck to the skin; a lead is the electrical view the machine builds by comparing electrodes. That is why ten electrodes, four on the limbs and six on the chest, yield twelve leads. Treating the words as interchangeable is the most common error, but it cannot be right, since ten sensors would then produce only ten views. The cable running from the machine is the patient cable or lead wire, which is a third thing entirely.

A technician arrives to record a 12-lead two days after chest surgery and finds a sterile dressing covering the V3 and V4 sites. What should the technician do?

• a.Take the dressing down, apply the electrodes on the marked sites, and tape the dressing back afterward
• b.Apply V3 and V4 on top of the dressing and press firmly so the gel makes contact through the gauze
• c.Leave V3 and V4 off, record the other ten leads, and write the reason for the omission on the printout
• d.Notify the nurse or your supervisor before the dressing is disturbed and follow the direction given✓

Taking down a surgical dressing is a sterile procedure outside the technician's scope, so the person responsible for the wound decides whether it comes off and when. Pressing an electrode onto gauze gives no skin contact, and the resulting flat or noisy trace is worse than no trace. Omitting two chest leads without asking anyone leaves an incomplete study that will have to be repeated, and the omission itself may be read as poor R wave progression. Reporting first and then recording under direction is the sequence that protects both the wound and the tracing.

A monitor technician at the central telemetry station sees new ST segment elevation in the monitoring lead of a patient who has just reported chest pressure to the nurse. What is the appropriate action?

• a.Save the strip and pass the change along to the nurse at the end of the shift
• b.Report the change to the nurse or your supervisor at once so a diagnostic 12-lead can be obtained✓
• c.Chart that the patient is having an anterior infarction and file the strip in the record
• d.Switch the display to a different lead and watch for several minutes to see whether the change resolves

At a central station the technician can see the signal but cannot see, touch, or assess the patient, so the fastest useful thing the technician can do is put the information in the hands of the people at the bedside. A monitoring lead can show that something has changed, but only a 12-lead recorded with standard placement can be used to work up an infarction, and chest pressure with a new ST change is time-critical. Reporting it at once so the ordered 12-lead is done is inside the technician's scope; recording a diagnosis such as anterior infarction in the chart is not. Saving the strip and passing the change along at the end of the shift is proper documentation delivered far too late, and hunting for a lead that looks better delays the study and can leave the change out of the record. Print and save the strip that shows the change so the report is backed by the tracing.

Which landmark does a technician use to start counting intercostal spaces before placing the chest electrodes?

• a.The sternal angle, where the second rib meets the sternum; the space just below it is the second intercostal space✓
• b.The notch at the top of the sternum, where the space lying just below the notch is the first intercostal space
• c.The lower tip of the sternum, counting upward from the space above the xiphoid process to the fourth space
• d.The lower border of the left clavicle, since the space directly beneath the clavicle is the second intercostal space

The sternal angle, also called the angle of Louis, is the ridge where the manubrium meets the body of the sternum, and the second rib joins the sternum there. Sliding the finger off that rib lands in the second intercostal space, and counting down two more spaces reaches the fourth, where V1 and V2 go. Starting at the suprasternal notch is the common error, because the first rib lies under the clavicle and cannot be palpated reliably, so the count starts one space off and shifts every chest electrode. Counting up from the xiphoid crosses the costal margin and is no more accurate; the space under the clavicle is the first, not the second.

In the standard order for applying chest electrodes, V4 is placed before V3. What is the reason for that order?

• a.V3 sits midway between V2 and V4, so V4 has to be in place first✓
• b.V4 gives the tallest complexes, so placing it first lets the machine set its gain
• c.V4 marks the horizontal line that V1 and V2 are then measured down from
• d.Placing V4 first keeps the technician from counting down the intercostal spaces twice

V3 has no landmark of its own: it is defined as the midpoint of a line between V2 at the fourth intercostal space at the left sternal border and V4 at the fifth intercostal space at the left midclavicular line. Until V4 is on the chest there is no second point to measure from, so a V3 placed first is a guess. Saving a second count of the intercostal spaces is a genuine convenience of this order, but convenience is not what makes the order necessary. Gain is set by the calibration signal at 10 mm/mV, and V1 and V2 are found by counting ribs rather than by measuring down from V4.

A technician places V1 and V2 in the second intercostal space instead of the fourth. What effect does this have on the tracing?

• a.Little effect on the tracing, as long as both electrodes are moved together by the same number of spaces
• b.The P waves there can invert and the tracing can imitate an anterior infarction✓
• c.The R wave voltage in those leads rises enough to suggest left ventricular hypertrophy
• d.The complexes in those leads shift below the baseline and the measured QT interval shortens

Electrodes set one or two spaces too high sit closer to the atria and farther from the ventricular mass, so the P waves in V1 and V2 can become negative and the R waves lose height. That loss of R wave height imitates an anteroseptal infarction, and an rSr pattern may appear as well, which is why superior misplacement is one of the errors most likely to change what a physician reads. Moving both electrodes together does not cancel the error, since the whole chest view is displaced toward the base of the heart. Misplacement of this kind lowers rather than raises R wave voltage in those leads and does not shorten the QT interval.

V6 is placed at the left midaxillary line. Which description identifies that landmark?

• a.The vertical line running down the front of the chest through the front fold of the armpit
• b.The vertical line running down the back of the chest through the lower tip of the scapula
• c.The vertical line dropped from the middle of the collarbone down through the nipple line
• d.The vertical line dropped from the top of the armpit, midway between its front and back folds✓

The midaxillary line falls from the apex of the axilla and lies midway between the anterior and posterior axillary folds, which places V6 on the side of the chest at the same horizontal level as V4 and V5. The line through the anterior fold is the anterior axillary line and belongs to V5, which is why that choice is the tempting one. The line through the middle of the clavicle is the midclavicular line, used for V4. The line at the tip of the scapula is a posterior landmark and is not used for any of the six standard chest leads.

A physician orders posterior leads on a patient with a suspected posterior infarction. Where does the V8 electrode go?

• a.At the left midscapular line, on the same horizontal level as V6✓
• b.At the left posterior axillary line, level with V4 and one space below V6
• c.Just to the left of the spine, one intercostal space above the level of V6
• d.Over the lower tip of the left scapula, two intercostal spaces below V6

The three posterior leads sit on one horizontal line continuing around from V6: V7 at the left posterior axillary line, V8 at the left midscapular line, and V9 at the left border of the spine. Because they stay level with V6, none of them is placed a space above or below it, which rules out the two answers that move up or down an interspace. The posterior axillary line is where V7 goes, not V8, and that is the closest wrong answer. The electrode near the spine is V9.

Under a common hospital protocol, a 15-lead EKG is ordered when right ventricular or posterior involvement is suspected. Which leads are added to the standard 12?

• a.V7, V8, and V9, spaced across the left side of the patient's back
• b.V3R, V4R, and V5R, spaced across the right side of the patient's chest
• c.V4R, V5R, and V6R, recorded in place of V4, V5, and V6 on the left
• d.V4R on the right chest, plus V8 and V9 on the left side of the back✓

The usual 15-lead protocol keeps all twelve standard leads and adds three: V4R to look at the right ventricle and V8 and V9 to look at the posterior wall, which is why one right-sided and two posterior leads appear together. Adding only the three posterior leads, or only the right-sided ones, gives a 15-lead count on paper but leaves one of the two suspected regions unexamined. Replacing V4, V5, and V6 would still be twelve leads, and it would discard the lateral views. Protocols vary between facilities, so the technician follows the order and labels every added lead on the tracing.

A monitor is set up to display the modified chest lead MCL1. Where does the positive electrode belong?

• a.At the fifth intercostal space at the left midclavicular line
• b.At the fourth intercostal space, right sternal border✓
• c.Below the left clavicle, close to the point of the left shoulder
• d.At the fifth intercostal space at the left midaxillary line

MCL1 imitates the view of V1, so its positive electrode goes where V1 goes, at the fourth intercostal space at the right sternal border, with the negative electrode near the left shoulder. That right-sided view separates right from left ventricular ectopy and shows atrial activity well, which is why monitors are often left in it. The fifth space at the left midclavicular line is the V4 position, and a positive electrode at the left midaxillary line makes MCL6, not MCL1. The spot below the left clavicle is where the negative electrode of MCL1 belongs.

Telemetry monitoring electrodes are applied to the torso rather than to the arms and legs. What is the main reason for this?

• a.Skin over the torso conducts the signal better than the skin covering the arms and the legs does
• b.Monitor cables are too short to reach the four limbs from a telemetry box carried at the waist
• c.The torso lies closer to the heart, so the complexes recorded there are tall enough to alarm on
• d.Limb electrodes pick up arm and leg movement, and torso placement keeps the rhythm readable as the patient moves✓

A monitored patient walks, eats, and turns in bed for hours, and electrodes on moving limbs fill the tracing with muscle artifact that buries the rhythm. Torso positions sit over bone and quieter tissue, so the complexes stay readable while the patient moves. Skin resistance is lowered by preparation rather than by the body part chosen, and cable length is a convenience rather than the reason. Torso placement is not chosen to make the complexes taller either; it shifts the recorded amplitudes enough that a monitoring tracing cannot stand in for a diagnostic 12-lead.

Why is a single continuous monitoring lead not used to rule in a myocardial infarction?

• a.The monitor runs the tracing at a slower paper speed, so ST segments cannot be measured on it
• b.The monitor filters the P wave out of the display, leaving only the QRS complex to review
• c.Torso electrode positions record voltages far too small for any measurement to be made
• d.One lead gives a single view of the heart and is meant for watching rhythm✓

Locating an infarction depends on seeing which region shows the change, and that takes the twelve views of a standard 12-lead; one monitoring lead offers a single angle and is intended to follow rhythm. The torso positions used for monitoring also shift the amplitudes, so the tracing is not comparable with a diagnostic recording, although the voltages are perfectly measurable. Monitors run at the same 25 mm/sec paper speed as an EKG machine and display the P wave, so neither of those explanations holds. A change seen on the monitor is reported and then a 12-lead is recorded.

In Einthoven's triangle, which two electrodes form lead II and what polarity does each carry?

• a.The right arm is the negative pole and the left leg is the positive pole✓
• b.The left arm serves as the negative pole and the left leg as the positive
• c.The right arm is negative and the left arm positive, with the leg as ground
• d.The left leg is the negative pole and the right arm the positive, giving tall waves

Einthoven's triangle is drawn between the right arm, the left arm, and the left leg, and lead II runs from the right arm as negative to the left leg as positive. That axis lies closest to the normal direction of depolarization, which is why lead II shows the most upright P waves and is the usual rhythm lead. The combination of left arm negative with left leg positive is lead III, and right arm negative with left arm positive is lead I, so both are real leads and neither is lead II. Reversing the poles of lead II would invert the complexes rather than enlarge them.

What does the word augmented describe in the augmented voltage leads aVR, aVL, and aVF?

• a.The machine doubles the paper speed for these three leads, so their complexes are printed wider
• b.Two extra electrodes are added to the limbs to raise the voltage that these leads can record
• c.These three leads are recorded at 20 mm/mV, which is twice the standard calibration setting
• d.The signal at a single positive electrode is small, so the machine increases it by about half✓

Each augmented lead compares one positive limb electrode with a reference made from the other two limb electrodes, and the resulting signal is small, so the machine boosts it roughly 50 percent to produce a readable complex. No extra electrodes are involved; the same four limb electrodes serve the three bipolar leads and the three augmented leads. The whole tracing is printed at one paper speed of 25 mm/sec and one calibration of 10 mm/mV, and the standardization mark at the start of the strip shows that the augmented leads share it. Changing the calibration would alter every lead, not only these three.

A woman in her third trimester of pregnancy becomes lightheaded and pale when she lies flat for a 12-lead EKG. Under a typical facility policy, what should the technician do?

• a.Seat her fully upright in a chair and record the tracing with the chest electrodes left in place
• b.Tilt her slightly onto her left side and record with the electrodes in their standard positions✓
• c.Keep her flat and work quickly, since a tracing recorded in any other position cannot be read
• d.Turn her onto her right side so that the weight of the uterus is carried away from the heart

Late in pregnancy the uterus can press on the inferior vena cava when the patient lies flat, reducing the blood returning to the heart and causing lightheadedness and pallor. Tilting the patient toward her left side moves the uterus off the vena cava, and a small wedge under the right hip achieves it while the electrodes stay on their anatomical landmarks. A right-sided tilt leaves the vena cava, which lies to the right of the spine, still compressed. Sitting fully upright changes the position of the heart within the chest, so any position other than the standard one is noted on the tracing for the physician who reads it.

On a finished tracing the R wave grows from V1 to V2, is clearly smaller in V3 than in V2, and then grows again in V4 and V5. What is the most likely cause?

• a.An old anterior infarction that has taken the R wave out of the middle chest leads
• b.The whole chest set applied one intercostal space lower than the correct positions
• c.Rotation of the heart within the chest, which flattens the middle chest leads
• d.The V2 and V3 electrodes were interchanged when the chest was set up✓

R wave height should build steadily from V1 through V5, and a single lead that steps backward and then recovers points to two neighboring electrodes swapped rather than to disease, since no infarction affects one lead and spares the leads on both sides of it. An old anterior infarction is the answer worth weighing, but it flattens a run of leads instead of producing one isolated dip. Placing the whole chest set a space low shifts all six leads together and does not break the sequence. Rotation likewise shifts the transition point smoothly rather than reversing it for one lead.

A completed 12-lead shows abnormal Q waves in V1, V2, V3, and V4. Which surfaces of the heart do those four leads view?

• a.The inferior surface of the heart, viewed from below by way of the left leg
• b.The lateral wall together with part of the inferior surface
• c.The posterior wall, which faces the spine behind the heart
• d.The septum together with the anterior wall of the left ventricle✓

V1 and V2 sit over the septum and V3 and V4 sit over the anterior wall, so a change running through all four is described as septal and anterior. The inferior surface is recorded by leads II, III, and aVF, and the lateral wall by leads I and aVL with V5 and V6. The posterior wall faces away from every standard chest electrode, which is why leads V7 through V9 exist. Naming the region the leads cover is reporting, not interpretation, and it is what the technician can say about a tracing.

A physician orders leads V3R through V6R on a patient in the emergency department. How are those four electrodes positioned?

• a.On the left chest, each one placed one intercostal space above its usual position
• b.On the back at the level of V6, spaced across the left shoulder blade
• c.On the right chest, mirroring the V3 through V6 positions across the sternum✓
• d.On the right chest, but one intercostal space higher than the left-sided positions

Right-sided chest leads are the mirror image of the standard ones: V4R goes to the fifth intercostal space at the right midclavicular line, V5R and V6R continue around the right chest at that same level, and V3R falls midway between V2 and V4R. The horizontal level does not change, so the answer that raises them an interspace describes no recognized position. Electrodes across the shoulder blade would be the posterior leads V7 through V9. Every right-sided tracing is labeled with the R designations, because unlabeled right chest leads read as an abnormal standard tracing.

A patient has a pacemaker generator lying directly under the usual V2 site, with a well-healed incision over it. What should the technician do?

• a.Place that electrode as near the correct site as the device allows and note the change✓
• b.Ask your supervisor whether an EKG may be recorded at all on a patient with a pacemaker
• c.Press the electrode down over the generator so that the site matches the standard position
• d.Leave that lead off and record the rest, marking the printout as incomplete

Electrodes are kept off implanted devices, incisions, and scars, so the electrode is moved the smallest distance that clears the generator and the change is written on the tracing for the reader. Placing it over the generator gives poor skin contact on a raised surface and presses on the pocket. Omitting a chest lead leaves an incomplete study that will have to be repeated, and the missing lead can be mistaken for lost R wave progression. A healed pacemaker pocket is not a reason to question whether the study may proceed, and the pacemaker spikes themselves are useful information for the physician.

During exercise testing the limb electrodes are moved onto the torso instead of the arms and legs. Why should that tracing not be compared with the patient's resting 12-lead?

• a.Torso placement drops the three augmented voltage leads from the printed tracing altogether
• b.Torso placement shifts the frontal plane axis and can imitate an inferior infarction✓
• c.Torso placement doubles the amplitude recorded in each of the six chest leads
• d.Torso placement records the rhythm alone, so no interval can be measured from it

Moving the limb electrodes onto the trunk changes the geometry of Einthoven's triangle, which rotates the frontal plane axis and alters the limb lead complexes; new Q waves or lost R waves in the inferior leads can appear from placement alone. That is why a torso-placed tracing is labeled as such and is compared only with other torso-placed tracings, not with a standard resting 12-lead. All twelve leads including the augmented ones are still produced, and every interval remains measurable. Chest lead amplitudes are affected far less than the limb leads, and they are not doubled.

On a 12-lead tracing, leads I and II carry the same fuzzy interference while lead III is clean. Which electrode is the most likely source?

• a.The right arm electrode, shared by leads I and II✓
• b.The left arm electrode, shared by lead I and aVL
• c.The left leg electrode, shared by leads II and aVF
• d.The right leg electrode, which serves as ground

Lead I records the left arm against the right arm and lead II records the left leg against the right arm, so the right arm electrode is the only site both of those leads use, and interference limited to that pair points straight at it. The technician reseats or replaces that electrode and inspects its wire. A failing left arm electrode would corrupt leads I and III, and a failing left leg electrode would corrupt leads II and III, so neither fits a clean lead III paired with dirty leads I and II. The right leg electrode is the ground reference, and trouble there shows up across the whole tracing rather than in two leads.

Every lead of a 12-lead tracing shows the same coarse interference, and the pattern does not change when the technician reseats individual electrodes. What does that pattern indicate?

• a.One limb electrode has lost contact with the patient's skin
• b.A lead wire has slipped off the electrode snap at its tip
• c.A chest electrode was placed over the sternum instead of a rib space
• d.The patient or the room, rather than one electrode, is the source✓

Trouble at one electrode can only corrupt the leads that use that electrode, so noise present in all twelve leads has to come from something common to the entire recording: the patient (tremor, shivering, movement), the surroundings (a nearby electrical device or power cord), or the ground and cable itself. The technician therefore looks at the patient and the room rather than continuing to swap single electrodes. A limb electrode that has lifted, a wire that has come off its snap, and a misplaced chest electrode each affect only their own leads and leave the rest of the tracing readable.

A monitor technician sees a completely flat, straight line in one monitored lead while the other displayed leads show normal complexes and the patient is sitting up talking. The nurse has just checked that lead's electrode at the bedside and reports that it is well adhered and that its gel is still moist. What is the most likely cause?

• a.A lead wire has pulled off its electrode or is broken internally✓
• b.The patient is in asystole and a code should be called at once
• c.The gel on that electrode has dried out and lost conductivity
• d.That electrode has slipped onto a bony area of the chest wall

A true straight line in one lead while the neighboring leads record normal complexes is an equipment failure, because the heart cannot stop for one lead and keep beating for the others. With the electrode itself confirmed as adhered and moist, the remaining break in the circuit is the wire: the technician traces it from the machine to the electrode, reconnects or replaces it, and confirms the display. Asystole appears in every lead at once and in a patient who is unresponsive and pulseless, not in one who is sitting up talking. Dried gel and an electrode sitting over bone degrade the signal into noise or low-amplitude waveforms rather than erasing every deflection, and the bedside check has already ruled the dried electrode out.

A technician is at the bedside finishing a 12-lead when the patient's monitor alarms and displays a wide, chaotic waveform that resembles ventricular fibrillation. What should the technician do first?

• a.Call the supervisor at once so that the code team can be activated
• b.Print a rhythm strip for the chart before doing anything else
• c.Switch the displayed lead to see whether the noise clears
• d.Check the patient at once for responsiveness and a carotid pulse✓

A monitor displays a signal, not a patient, and the only way to separate true ventricular fibrillation from artifact created by toothbrushing, chest percussion, or a scraped electrode is to look at the patient and feel for a pulse. Standing at the bedside, the technician can do that in seconds, which is why the assessment comes first here; a technician watching the same waveform from a central station cannot touch the patient and would have to send help to the room instead. A patient who is awake with a pulse is generating artifact, and a patient who is unresponsive and pulseless needs help immediately, so the bedside check drives everything that follows. Calling for the code team before anyone has laid eyes on the patient starts a resuscitation on someone who may be brushing their teeth; escalation follows the assessment rather than replacing it. Printing a strip or changing the displayed lead costs seconds that matter if the rhythm is real.

A patient with Parkinson disease has a resting tremor of both hands that fills the limb leads with continuous spiky artifact. What should the technician do?

• a.Move all four limb electrodes up onto fleshy sites on each limb✓
• b.Ask the patient to hold both hands still until the recording ends
• c.Have the patient sit up and grip the table edge to steady the arms
• d.Halve the sensitivity to 5 mm/mV so the spikes look smaller

Tremor artifact is generated by the skeletal muscle underneath the electrode, so moving all four limb electrodes proximally onto fleshy areas of the upper arms and thighs, keeping the four symmetric, puts them over quieter muscle; supporting the limbs on the bed helps further, and the altered placement is noted on the tracing. A resting tremor is involuntary and a patient cannot suppress it on request. Sitting up and gripping something tenses the arm and shoulder muscles and makes the artifact worse. Cutting the sensitivity in half shrinks the artifact and the QRS complexes by the same amount, so nothing is gained and the tracing is no longer standard.

During a resting 12-lead EKG the patient keeps talking and turning to look at the machine, and the tracing fills with irregular jagged deflections. What should the technician do?

• a.Report the poor tracing to the supervisor and let the nurse repeat it
• b.Accept the tracing and write "patient was moving" across the bottom
• c.Ask the patient to lie still and stay quiet, then record the tracing again✓
• d.Hold the patient's arms down gently against the bed while recording

Talking and turning contract the chest, neck, and shoulder muscles, and their electrical activity lands on the tracing as jagged somatic artifact. Because the recording itself takes only about ten seconds, telling the patient how brief it is and coaching stillness usually solves the problem outright, and a clean repeat costs almost nothing. Handing a movement-degraded tracing to the chart with a note leaves an unreadable study in the record, and handing the whole task upward for a problem the technician can fix at the bedside wastes the patient's and the nurse's time. Physically holding a patient down is outside a technician's scope and adds the muscle tension it is meant to prevent.

The baseline in lead V3 wanders up and down while every other lead sits steady and the patient is breathing quietly. What is the most likely cause and correction?

• a.That electrode is losing contact; apply a fresh one to the site✓
• b.The patient is breathing deeply; coach slow, shallow breathing
• c.The room is cold; cover the patient and warm the room, then rerun
• d.The cable lies on a power cord; separate the two, then rerun

A cause that acts on the patient as a whole, such as respiration or shivering, moves the baseline in many leads at once, so drift confined to a single lead localizes the problem to that one electrode's contact with the skin. Adhesive that is lifting or gel that is drying lets the contact resistance change from moment to moment, and the baseline follows it. Deep breathing would sway the chest leads together and would track the patient's respiratory rate, which is not what is happening here. A cold room produces muscle noise in several leads, and a cable running along a power cord produces a fine fuzzy band rather than a slow wandering baseline.

The chest lead wires hang straight down over the side of the bed, and the tracing shows repeated abrupt baseline shifts. What should the technician do?

• a.Lay the wires along the body with slack so they do not pull✓
• b.Press each chest electrode down harder and record the tracing again
• c.Tape the patient's gown over the wires to hold them against the bed
• d.Replace all six chest electrodes before recording again

Hanging wires put steady traction on the electrode snaps, and every small tug shifts the skin-to-electrode contact and jumps the baseline. Routing the wires along the contour of the patient's body with a little slack, so the cable carries its own weight, removes the traction and the jumps with it. Pressing harder on electrodes that are already stuck does nothing about the pull on them. Taping the gown over the loaded wires still leaves them under tension and can drag the electrodes when the patient shifts, and fresh electrodes would simply be pulled on by the same hanging wires.

A heavily diaphoretic patient's chest electrodes peel off within seconds of being applied. What is the appropriate response?

• a.Add extra conductive gel under each electrode before pressing it on
• b.Hold each electrode down for a full minute so it can set
• c.Record the tracing quickly, before the electrodes have time to lift
• d.Dry the skin, apply fresh electrodes, and secure them with tape✓

Sweat is a fluid layer between the adhesive and the skin, so nothing sticks until the site is dried; the technician pats each site dry, applies new electrodes, and holds them with tape or a wrap for the length of the recording. Many facilities also stock a skin-prep or antiperspirant product for this situation, and technicians should follow local policy on which is used. Extra gel makes the surface wetter still and can let signal bridge between neighboring chest sites. Pressing longer, or racing the recording, does not change the fact that the adhesive has no dry surface to grip.

Before a 12-lead EKG, a patient says that electrode adhesive has previously caused blistering and a spreading rash. What should the technician do?

• a.Apply the usual electrodes and take them off as soon as the tracing prints
• b.Apply the electrodes over a thin gauze square to protect the skin
• c.Report the reaction to the supervisor and use hypoallergenic electrodes✓
• d.Cancel the test and chart the reported reaction using the patient's own words

Blistering and a spreading rash describe a genuine contact allergy, so the technician stops before applying anything, passes the history to the nurse or supervisor so it is documented, and uses the latex-free, low-adhesive electrodes that facilities stock for this purpose. Applying the usual electrodes and removing them quickly still delivers the allergen to the skin and is a foreseeable injury. Gauze between the gel and the skin blocks conduction and produces an unusable tracing. A technician does not cancel a test that has been ordered; documenting the history is necessary but does not by itself get the study done safely.

A technician suspects that an infusion pump plugged in beside the bed is feeding interference into a monitored patient's tracing. What is the appropriate step?

• a.Move the patient cable and lead wires away from the pump and its power cord✓
• b.Unplug the infusion pump briefly to see whether the interference clears
• c.Display a different lead so that the interference is less noticeable
• d.Move the patient to another room and repeat the recording there

Interference from mains-powered equipment couples into the patient cable by proximity, so putting distance between the cable, the device, and the power cord is both the first correction and the safest one, and it usually works within a few inches. An infusion pump is delivering therapy, and interrupting a running infusion to test a theory about artifact is outside a technician's scope. Changing the displayed lead hides the noise without removing it, and the artifact will still be sitting on the recorded tracing. Relocating a patient is disruptive, often impossible, and unnecessary when routing the cable away from the cord solves the same problem.

In a dry room, sharp isolated spikes appear on the tracing each time the technician adjusts the synthetic blanket covering the patient. What is the most likely cause?

• a.Static discharge through the patient✓
• b.Alternating current from the bed's motor unit
• c.Muscle tremor from a patient who feels cold
• d.A lead wire broken inside its insulation

Nylon and other synthetic fabrics build up a charge in dry air, and each movement of the fabric discharges through the patient and the electrodes as a sharp, irregular spike that stops as soon as the fabric stops moving; changing to cotton coverings removes it. Alternating-current interference is a continuous, uniform band of small oscillations rather than isolated spikes tied to one person's hand. A cold, shivering patient produces continuous irregular fuzz across several leads rather than discrete spikes. A wire broken inside its insulation makes one lead flat or grossly erratic, and the disturbance would not be timed to the movement of the covers.

Why does a technician lightly abrade each electrode site with a dry gauze square or the abrasive tab on the electrode?

• a.It warms the site so that the conductive gel spreads more evenly
• b.It sterilizes the site so the electrode cannot introduce infection
• c.It removes dead surface skin, which lowers resistance to the signal✓
• d.It closes the pores so perspiration cannot loosen the electrode

The outer layer of dead skin cells is a poor conductor and is the largest source of resistance between the heart's signal and the electrode, so scrubbing it away with gauze or the abrasive patch on the electrode measurably cleans up the tracing. The abrasion is deliberately light: reddening the skin is enough, and it should stop well short of breaking the skin or drawing blood. Abrading is not a sterilizing step, and skin preparation for a surface EKG is not a sterile procedure. Rubbing does not warm the site in any way that changes gel behavior, and pores cannot be closed by friction.

A technician has replaced the electrodes, prepared the skin again, rerouted the cable, and coached the patient, and the tracing is still too noisy to be read. What should be done?

• a.Record it anyway and mark it as an acceptable study
• b.Reduce the sensitivity until the noisy baseline looks flatter
• c.Print the cleanest attempt and file it without any comment
• d.Tell the supervisor and document what was tried✓

Once the correctable causes have been worked through, the remaining step belongs to someone with more authority: the supervising nurse or supervisor decides whether a limited study is acceptable or whether the test is repeated later, and the record shows what was attempted so the reader knows the disturbance is technical rather than cardiac. Marking a noisy tracing as an acceptable study, or quietly filing the least bad attempt, invites a reader to interpret artifact as pathology. Lowering the sensitivity shrinks the noise and the complexes together, producing a non-standard tracing that is no easier to read.

A 12-lead tracing contains a five-second burst of artifact that occurred as the patient reached for a tissue. What is the appropriate way to handle the record?

• a.Delete the affected seconds from the stored file and print the rest
• b.Annotate the burst on the tracing as a short run of ventricular tachycardia
• c.Leave the burst unmarked so that the reader's judgment is not influenced
• d.Record the tracing again once the patient is settled and note the cause of the burst✓

The remedy for a movement burst is another ten-second acquisition, plus a short factual note of what the patient was doing, which lets the interpreting provider see immediately that the disturbance was mechanical. Deleting seconds from a stored file alters a medical record and hides information that the reader is entitled to. Writing a rhythm name on the tracing is interpretation and outside a technician's scope, and labeling artifact as ventricular tachycardia can set off treatment the patient does not need. Sending the burst through with no comment at all leaves the reader guessing and risks exactly the same misreading.

A patient arrives for a 12-lead EKG wearing a long metal necklace that lies across the chest and metal-framed eyeglasses, and has a stainless steel hip prosthesis. Which is most likely to disturb the tracing?

• a.The necklace, if it touches an electrode or a lead wire✓
• b.The hip prosthesis, since metal in the body conducts
• c.The eyeglass frames, since metal picks up room noise
• d.The prosthesis and necklace equally, both being metal

Metal lying on the skin can bridge across an electrode or drag against a lead wire as the patient breathes and moves, so a necklace draped over the chest is moved aside or removed before the chest electrodes go on. An implanted prosthesis is enclosed in tissue with no connection to the surface or to the cable, and it does not disturb the surface recording. Eyeglass frames sit far from every electrode and from the cable and have no path into the tracing. What matters is not whether metal is present but whether it can contact the recording circuit.

A confused patient repeatedly pulls the telemetry electrodes off, and the monitor alarms for a lost lead each time. What should the technician do?

• a.Tape the patient's hands to the bed rails until the leads stay on
• b.Report the situation to the supervisor for reassessment✓
• c.Silence the alarm and leave the leads off until the next shift
• d.Reapply the electrodes each time and add extra tape over them

Repeatedly pulling at monitoring equipment is a change in the patient's condition and a safety problem, so passing it to the supervising nurse or supervisor gets the patient reassessed and the monitoring plan adjusted. Applying restraints requires an order and is outside a technician's scope. Silencing the alarm and leaving the patient unmonitored removes the only warning the unit has that something is wrong. Simply reapplying and taping harder addresses the tracing but not the reason the patient is pulling, and it can injure fragile skin over repeated attempts.

A tracing shows a rapid, saw-toothed-looking baseline. Which finding points to somatic tremor rather than atrial flutter?

• a.Several leads have a clean, flat baseline✓
• b.The undulations are identical in every lead
• c.The ventricular rate sits near 150 beats per minute
• d.The waves stand out best in leads II, III, and aVF

Atrial activity is generated inside the heart, so flutter waves appear in every lead of the tracing, and a baseline that is completely clean in some leads while others oscillate has to come from muscle underneath particular electrodes. Flutter waves are also identical to one another and continue at a fixed atrial rate of roughly 250 to 350 per minute, often conducting two to one and giving a ventricular rate near 150 beats per minute, whereas tremor oscillations vary in both size and spacing. Because the two can look alike at a glance, the technician settles and supports the limb and repeats the tracing: artifact clears with the repeat and flutter does not.

During a 12-lead recording the two arm leads show fine, irregular baseline noise. The patient's right arm is hanging unsupported over the edge of the table. What should the technician do?

• a.Replace the electrode on that arm and repeat the recording
• b.Ask the patient to hold the arm straight out, away from the table
• c.Rest the arm flat and supported on the table beside the patient✓
• d.Turn on the artifact filter and repeat the recording

An arm that hangs unsupported keeps the shoulder and arm muscles working to hold it up, and that muscle activity is what puts the fine, irregular noise on the limb leads, so laying the arm flat and fully supported lets the muscles relax and the baseline settle. Holding the arm out in the air increases the muscle tension that is generating the noise. The artifact filter smooths the display without removing the cause, and it can blunt real detail such as the height of small waves, so it is not a substitute for correcting the position. Changing the electrode does nothing about the position that is producing the artifact in the first place.

A patient with persistent hiccups is being recorded, and tall, sharp deflections appear on the strip about once every two seconds. What should the technician do?

• a.Mark the deflections on the tracing as premature ventricular complexes
• b.Record a longer strip and note on it that the patient is hiccupping✓
• c.Wait until the hiccups have stopped before recording the tracing
• d.Apply a new set of electrodes and record the tracing over again

Hiccups are sudden diaphragmatic contractions that jolt the chest wall, and each one drops a sharp deflection onto the tracing at the rate of the hiccups rather than at any rate related to the underlying rhythm. A longer sample plus a factual note of the cause lets the interpreting provider match the deflections to the hiccups and separate them from genuine ectopic beats. Naming them premature ventricular beats is both an interpretation and a wrong one. New electrodes cannot exclude an artifact that the patient's own diaphragm is producing, and postponing an ordered study for hiccups that may last hours delays the patient's care.

A rhythm strip is labeled 50 mm/sec, and the QRS complexes on it measure five small boxes wide. What is the QRS duration?

• a.0.10 second, because each small box is 0.02 second at that speed✓
• b.0.20 second, because a small box is 0.04 second on any tracing
• c.0.05 second, because the box count is halved before converting it to time
• d.0.40 second, because a small box covers 0.08 second at that speed

Doubling the paper speed to 50 mm/sec spreads the tracing over twice as much paper, so each small box represents 0.02 second instead of 0.04 second: five boxes times 0.02 second equals 0.10 second, a normal QRS. Reading those same five boxes at 0.04 second each gives 0.20 second and would turn a normal QRS into an apparently wide, abnormal one. Halving the box count first, or treating a small box as 0.08 second, has no basis: changing the speed changes what a box is worth, not how many boxes the complex occupies. The recorded speed is printed on the tracing for exactly this reason.

An interpreting physician receives a 12-lead on which the standardization pulse measures 5 mm tall. What does that tell the physician about the tracing?

• a.The paper speed was lowered to 12.5 mm/sec, which compresses the complexes vertically
• b.It was run at half standard, so recorded amplitudes are half the true voltage✓
• c.The machine's calibration has drifted and the tracing must be repeated before it is read
• d.An artifact filter was applied, which cut the height of the calibration pulse in half

A standardization pulse 5 mm tall means the machine was set to 5 mm/mV, or half standard, so 1 mV produced only 5 mm of deflection instead of the usual 10 mm, and every measured amplitude must be doubled to recover the patient's true voltage. Half standard is a deliberate setting, chosen when complexes are so tall they overlap the channel above, and the pulse is printed precisely so the reader knows which gain was used. Paper speed changes the horizontal scale only and cannot shorten a complex. A machine whose calibration had genuinely drifted would not announce it with a clean, square 5 mm pulse, and filters do not rescale the calibration mark.

Muscle tremor artifact persists on a resting 12-lead after the technician supports the patient's arms and warms the room. The technician considers switching on the machine's artifact filter. What is the concern about relying on that filter?

• a.Filtering can distort the ST segment and reduce amplitude, so its use is noted on the tracing✓
• b.The filter erases the standardization pulse, leaving the reader no record of the settings used
• c.The filter works only at a paper speed of 50 mm/sec, so intervals need recalculating
• d.The filter removes 60-cycle interference only, so it has no effect on tremor artifact

An artifact or muscle filter narrows the frequency range the machine records; that smooths tremor, but it also alters the recorded waveform and can distort the ST segment and blunt QRS amplitude, which matters when the tracing is being read for ischemia. The better first move is to remove the cause at the patient, and when a filter is used the setting is printed or noted so the interpreter knows the tracing was filtered. The 60-cycle filter is a separate setting aimed at alternating-current interference, so a muscle filter does act on tremor. Filtering does not erase the calibration pulse and is independent of the paper speed.

A technician discovers that a 12-lead recorded an hour ago was printed under another patient's name and has already been filed in that patient's chart. What should the technician do?

• a.Cross out the wrong name, write the correct patient's name above it, and initial the change
• b.Pull the tracing from the chart, shred it, and record a new 12-lead on the correct patient
• c.Leave the tracing in place, since the interpreting physician will notice that it does not fit
• d.Report the error to a supervisor and follow the facility's correction policy✓

A tracing that has been filed is part of the medical record, and a technician does not alter it, discard it, or relabel it independently. Reporting the misidentified tracing so the facility's correction procedure can be followed produces a documented correction or addendum, a new tracing on the correct patient, and a trail showing who found the error and when. Crossing out a name and writing over it hides the change and leaves the other patient's chart still carrying a foreign result. Shredding destroys a record that has already been filed. Leaving it alone risks a patient being treated on the basis of someone else's tracing.

A technician has just recorded a resting 12-lead and is about to send it to the ordering provider. Which check must be completed before the tracing leaves the technician?

• a.That the heart rate printed by the machine matches a rate the technician counts by hand from the strip
• b.That the computerized interpretation printed by the machine agrees with the symptoms reported
• c.That patient identifiers, date and time, and technician identification are on the tracing and all 12 leads are legible✓
• d.That the patient has been shown the tracing and told which portions of it look normal before leaving

A tracing is not finished until it is identifiable and readable: full patient identifiers, the date and time of the recording, who recorded it, correct lead labels, all 12 leads present and legible, and a legible standardization mark showing the gain and speed used. Checking the machine-printed rate by hand is sound practice but is not what makes the record valid or attributable. Comparing the computerized statement with the patient's symptoms is interpretation and lies outside the technician's scope. Telling the patient which parts of the tracing look normal is also interpretation, and it is left to the provider even when the tracing appears unremarkable.

What does the transmitter worn by a patient on telemetry monitoring do?

• a.It stores the whole monitoring period in memory for a physician to download once the electrodes come off
• b.It analyzes the rhythm at the bedside and prints a 12-lead tracing whenever an alarm limit is crossed
• c.It delivers a small pacing stimulus if the patient's heart rate falls below the programmed low limit
• d.It converts the signal picked up by the electrodes into a radio signal that a central monitoring station receives and displays✓

Telemetry is live monitoring: the electrodes feed a small battery-powered transmitter the patient carries, and that unit sends the signal by radio to a receiver at a central station where the rhythm is watched continuously and stored there. Holding the entire recording in the device for later download describes a Holter monitor, which is reviewed after the fact rather than watched in real time, and that is the distinction most often missed. The transmitter itself does not analyze rhythms or print 12-leads; the central station displays, stores, and prints, and interpretation belongs to the provider. No telemetry transmitter paces the heart, which requires an implanted or external pacemaker.

Which practice protects a telemetry transmitter and its lead wires from failing during monitoring?

• a.Check the battery at the start of each shift and replace lead wires that are cracked or frayed✓
• b.Wrap the lead wires tightly around the transmitter case between patients so that they do not tangle
• c.Grasp the wire itself rather than the connector when taking a lead off an electrode
• d.Take the battery out whenever the patient leaves the unit so it does not run down

A transmitter is only as good as its power source and its wires, so batteries are checked and changed on the schedule the facility sets, and any wire with cracked insulation, a frayed conductor, or a bent pin is taken out of service because it produces intermittent signal loss and false alarms. Coiling wires tightly around the case stresses the conductor where it enters the housing and is a common cause of failure. Pulling on the wire instead of the connector damages that same junction. Removing the battery leaves the patient unmonitored without any record that monitoring stopped; a planned absence from the unit is handled through the facility's standby procedure instead.

The QRS complexes on a 12-lead are so small that the technician cannot measure their amplitude reliably. Which action addresses this?

• a.Record the tracing at double standard, 20 mm/mV, and note that setting✓
• b.Raise the paper speed to 50 mm/sec so the complexes are drawn taller
• c.Double each measured amplitude by hand and write the corrected values onto the tracing
• d.Record at half standard, 5 mm/mV, so more of each complex fits inside the channel

Low-amplitude complexes are handled at the machine rather than on paper: setting the sensitivity to 20 mm/mV makes 1 mV produce 20 mm of deflection, and the standardization pulse then prints 20 mm tall so the interpreter can see that every amplitude must be halved to recover true voltage. Paper speed changes only the horizontal scale, so running at 50 mm/sec spreads the complexes out without adding any height. Half standard shrinks them further, which is the opposite of what is needed. Writing corrected numbers onto the tracing alters a record the technician may not change, and it is unnecessary once the gain is documented by the calibration pulse.

A monitored patient is going off the unit for an approved test, and the nurse asks the technician to place that bed in standby on the central monitor. What must the technician keep in mind about standby on most monitoring systems?

• a.Standby keeps recording the patient's rhythm in the background and stores it for review after the return
• b.Standby automatically widens the alarm limits until the patient is back on the unit
• c.Alarms and monitoring are suspended, so the bed is taken off standby as soon as the patient returns✓
• d.Standby routes the patient's rhythm to the monitor in the department receiving the patient

Standby is a documented pause: on most systems it suspends the display, the alarms, and the recording for that bed so a patient who is legitimately off the unit does not generate a stream of false alarms. Because nothing is being watched during the pause, the bed has to be returned to active monitoring the moment the patient is back, and the time the pause started and ended is documented. Assuming the system keeps recording in the background is what leaves a patient unmonitored for hours after a return no one noticed. Standby does not adjust alarm limits, and it does not follow the patient to another department's monitor.

The central monitoring station alarms for asystole on a telemetry patient. What should happen first?

• a.Silence the alarm and watch the next several complexes to see whether the rhythm comes back
• b.Print a strip of the event and enter it in the monitoring log before anyone leaves the station
• c.Someone goes to the patient's bedside and checks the patient at once✓
• d.Notify your supervisor and wait for direction before anyone approaches the patient's room

Asystole on a monitor is treated as real until the patient shows otherwise, so the first action is to get eyes on the patient: a loose electrode, a detached lead wire, or a dead transmitter battery produces a flat line on a wide-awake patient, and only looking at the patient separates that from an arrest. Silencing the alarm and waiting for the rhythm to return spends the minutes that decide the outcome when the event is genuine, and alarms are not disabled or set outside safe limits to keep a station quiet. Printing and logging the event is required, but it follows the patient check. Escalating and waiting outside the room delays an assessment anyone at the bedside can make immediately, and notification happens alongside the response rather than in place of it.

A technician is cleaning an EKG machine and its patient cables between patients. Which practice is correct?

• a.Soak the cables in a basin of disinfectant so the solution reaches the connector pins and clips
• b.Rinse the cables under warm running water and dry them with a towel before storing the machine
• c.Disinfect the machine surfaces only when the patient tested is known to carry a resistant organism
• d.Wipe the cables and machine surfaces with a facility-approved disinfectant, observe the label's contact time, and let them dry✓

Cables, lead wires, and the surfaces a patient contacts are wiped between patients with a disinfectant approved for that device, kept wet for the contact time printed on the product label, and allowed to dry, which is what actually kills organisms without destroying the equipment. Immersing a cable or running it under water drives fluid into the connector and corrodes the pins, and the damage surfaces later as intermittent artifact or a dead lead. Cleaning only after a patient known to carry a resistant organism ignores every colonized patient nobody has identified. The manufacturer's instructions govern which product may be used, since some solutions degrade cable insulation.

A billing clerk asks an EKG technician to send a patient's entire inpatient chart so that a claim for one 12-lead can be processed. Applying the HIPAA minimum necessary standard, what should the technician do?

• a.Send the whole chart, because billing staff are workforce members with access
• b.Send nothing until the patient signs an authorization in writing
• c.Release only the order, the tracing, and the data needed to bill it✓
• d.Refuse the request, because billing disclosures need a court order

The minimum necessary standard limits any use or disclosure to the information actually needed for the purpose at hand, and billing one 12-lead needs the order, the tracing, and the demographic and coverage data rather than the full chart. Disclosures for payment are permitted without a signed authorization, so waiting for the patient's signature would stall a legitimate claim, and no court order is involved in routine billing. Being a workforce member does not entitle a clerk to everything in a record; access is limited by role and by purpose. The recognized exception to minimum necessary is a disclosure to another provider for treatment, which this request is not.

A technician steps away from the EKG cart to fetch a stretcher and leaves a completed tracing with the patient's name displayed on the cart screen in a hallway. What is the correct assessment of this situation?

• a.It is acceptable because the hallway lies inside a restricted clinical unit
• b.Leaving readable patient data unattended defeats the required safeguards✓
• c.It is a concern only if someone without access reads the screen
• d.It falls outside privacy rules because the tracing was not yet printed

Patient data displayed on an unattended screen is protected health information sitting in the open, and the safeguard requirements cover workstation and device security regardless of whether anyone is caught reading it. The screen should be cleared or locked, or the cart kept attended. A restricted unit still has visitors, transport staff, and other patients moving through it, so the location does not remove the exposure. Waiting for proof that someone read the display makes the safeguard meaningless, and an on-screen tracing is patient data whether or not paper has come out of the machine.

A patient's adult son stops the technician in the corridor and asks how his mother's EKG turned out. The mother has not agreed to have her information shared with him. What should the technician do?

• a.Give him a general summary, since immediate family may receive results
• b.Answer once he produces identification showing that he is her son
• c.Explain that results come from her provider and direct him there✓
• d.Tell him only whether the tracing was normal or abnormal today

Two separate rules point the same way here: the technician does not interpret a tracing for anyone, and the mother has not agreed to sharing, so the son is directed to the provider who ordered the study. Being immediate family creates no automatic right to a result; disclosure to a relative involved in care depends on the patient's agreement or, when she is unavailable, on professional judgment by the treating staff. Identification proves who a person is, not that the patient wants him told. Saying only whether the tracing was normal or abnormal is still both a disclosure and an interpretation.

Midway through acquiring a 12-lead, a patient says she has changed her mind and wants the technician to stop. The electrodes are still attached and the recording is not complete. What should the technician do?

• a.Finish the few remaining seconds, because stopping now wastes the study
• b.Explain that the consent she gave at the start covers the whole procedure
• c.Notify the supervisor before continuing so the order is not left undone
• d.Stop at once, remove the electrodes, and document that consent was withdrawn✓

Consent may be withdrawn at any point, and continuing to touch a patient who has told the technician to stop is battery no matter how little of the tracing remains. The correct sequence is to stop, remove the electrodes, tell the patient what happens next, and document the withdrawal and the notification of the ordering provider. Treating the initial agreement as covering the rest of the procedure misstates how consent works. Escalating the question first is wrong here because it leaves the technician working on a patient who has already refused; the stopping cannot wait for anyone else's decision.

A charge nurse asks an EKG technician to pull a patient's femoral sheath after a cardiac catheterization, a task the technician has had no training in performing. What should the technician do?

• a.Carry out the task, because a licensed nurse has delegated it
• b.Carry out the task while the nurse watches and corrects any error
• c.Read the facility procedure and attempt the removal once carefully
• d.Decline, state that the task is outside her training, and tell the supervisor✓

A delegated task is accepted only when it falls within the technician's scope and the technician is trained and competent to perform it; delegation by a licensed person does not transfer competence. Declining and routing the request through the supervisor gets the patient a qualified caregiver and puts the staffing gap where it can be fixed. Performing an untrained invasive task under observation is still performing it, and a bleeding femoral site leaves no time to correct an error. Reading a written procedure is not training, and a first attempt learned from a manual is exactly the conduct that falls below the standard of care.

While placing chest electrodes on an older adult outpatient, a technician sees patterned bruises in several stages of healing, and the relative who brought her answers every question directed to the patient. What should the technician do?

• a.Ask the relative how the bruises happened before recording it in the chart
• b.Chart nothing about the bruises, since a technician cannot substantiate abuse
• c.Photograph the bruises with the department camera for the record
• d.Document the objective findings and report the concern to the supervisor✓

Health care workers in most states are mandated reporters of suspected abuse of an older adult, and the threshold is reasonable suspicion, not proof. Recording exactly what was seen, in neutral descriptive terms, and routing the concern up the chain of command starts the process the facility and the state require. Questioning the accompanying relative can alert a possible abuser and put the patient at greater risk. Declining to chart the finding destroys the only contemporaneous record of it, and photographs of injuries are taken only under a specific facility or forensic protocol, not by a technician on her own initiative.

A technician posts an image of an unusual rhythm strip to a closed social media group for cardiac technicians, having cropped away the name field and the date. What is the problem with the post?

• a.There is no problem, because the identifiers were cropped out of the image
• b.The post is acceptable only if the group is limited to health care workers
• c.The tracing is still patient information, and posting it discloses it without authorization✓
• d.The post becomes a violation only when a member of the group recognizes the patient

A tracing is information created about an identifiable individual, and cropping the visible name field does not by itself de-identify it, because the date, the device, the setting, and the clinical detail can still point back to one person. Sharing it outside the facility for a purpose other than treatment, payment, or operations requires the patient's written authorization. A closed group is still an audience with no treatment relationship to the patient, so limiting membership to clinicians does not create permission. Waiting until someone recognizes the patient misstates the rule, since the disclosure is complete at the moment of posting.

An EKG technician notices that a coworker on the same shift smells of alcohol and is slurring words while connecting a patient's lead wires. What should the technician do?

• a.Report the observation to the supervisor now✓
• b.Wait until the shift ends and ask the coworker
• c.Finish the tracing and speak with him privately
• d.Note the concern in the patient's chart instead

An apparently impaired coworker is an immediate patient-safety problem, and every facility routes that concern up the chain of command at once so the coworker can be removed from patient care and evaluated. Waiting until the end of the shift leaves an impaired worker on patients for hours. A private conversation is a reasonable instinct for a minor performance issue but not for suspected impairment, where the technician has no way to assess fitness and no authority to remove anyone from duty. The patient's chart is a record of that patient's care, so a note about staff conduct does not belong in it.

A staff nurse looks at a tracing the technician has just acquired and asks whether it looks like a heart block. What is the appropriate response for the technician?

• a.Offer an opinion, since a nurse and not the patient is asking the question
• b.State that the machine's printed interpretation is the official reading
• c.Decline to comment and say nothing further about the tracing
• d.Describe what was observed and note that a provider must interpret it✓

Reporting objective observations is part of the technician's job: the measured rate, whether the rhythm is regular, and what the machine printed are all facts that can be handed to the nurse. Attaching a diagnosis to them is not, whoever is asking, because interpretation belongs to the physician or other qualified provider. The computer statement on the printout is explicitly unconfirmed until a physician reads and signs the tracing, so calling it official is wrong and can propagate an error. Refusing to say anything at all overcorrects and withholds information the nurse legitimately needs to prioritize care.

An outpatient asks the technician for a copy of the tracing that was just recorded, saying she wants it for a second opinion elsewhere. What should the technician do?

• a.Explain that patients receive the physician's report rather than raw tracings
• b.Tell her she has a right of access and send her to health information management✓
• c.Print a second copy and hand it to her after checking her wristband
• d.Ask the supervisor to release the tracing at the end of the visit

A patient has a right of access to her own designated record set, and the tracing is part of it, so the answer is not refusal but referral to the department that verifies identity, logs the request, and releases the record within the required time. Telling her that only the physician's report may be released misstates that right. Handing over a copy at the machine skips the verification and the accounting that the records process exists to provide, even though the wristband was checked. Routing the request to the supervisor is unnecessary and simply delays a request the records department handles as a matter of routine.

A nurse asks an EKG technician to run a 12-lead on an alert, stable patient because the patient looks unwell, but no order for the tracing has been entered. What should the technician do?

• a.Perform the tracing, since a nurse's verbal request functions as an order
• b.Perform the tracing and have the order entered into the chart afterward
• c.Explain that an order is required and notify the supervisor of the nurse's concern✓
• d.Refuse and tell the nurse to have the provider come to the bedside first

A diagnostic test is performed on a provider's order, and a technician working without one has acted outside the scope of the job and left the study unbillable and unowned. Explaining the requirement and passing the clinical concern up the chain gets the order entered quickly while keeping the patient's deterioration visible to someone who can act on it. Treating a nurse's request as an order confuses a request with authorization; a nurse may take a verbal order from a provider, but the technician has no such order here. Performing the tracing and back-filling the order documents an event that did not happen in the sequence charted. Simply refusing and walking away drops a stated clinical concern about a patient.

A scheduled outpatient walks into the EKG room, sits down, and begins unbuttoning her shirt as the technician explains the test. Which form of consent does her behavior represent?

• a.Informed consent, because the procedure was explained first
• b.Implied consent, shown by her cooperation✓
• c.Written consent, satisfied by the registration paperwork
• d.Expressed consent, given when she booked the appointment

Consent inferred from a patient's cooperative conduct is implied consent, and it is what a routine noninvasive 12-lead relies on. Informed consent is a documented discussion of risks, benefits, and alternatives conducted by the provider performing an invasive or higher-risk procedure, so explaining the steps of a tracing does not convert this into informed consent. General registration paperwork is a consent to treat and is not the specific written consent form used for a procedure. Expressed consent is a spoken or written statement of agreement, and booking an appointment is not that statement.

A technician discovers that a comment she entered in the electronic record an hour earlier lists the wrong room number. How should the entry be corrected?

• a.Delete the entry from the record and re-enter the information correctly
• b.Ask the supervisor to have the records office remove it
• c.Use the amendment function so the original entry remains visible✓
• d.Leave the entry and note the mistake in the next shift note

An electronic record is corrected through the system's amendment or addendum function, which stores the new text alongside the original and stamps who changed what and when. Deleting the entry destroys part of a legal record and shows up in the audit trail as exactly that. Routing a routine self-caught error to the records office through the supervisor is neither necessary nor how correction rights work, since the author corrects her own entry. Leaving the error uncorrected and mentioning it elsewhere leaves the wrong information in the place where the next reader will look.

An employer telephones the clinic and asks for the result of a pre-employment EKG that one of its applicants completed there. What is required before the result may be released?

• a.The general consent to treat that the patient signed at registration
• b.A verbal agreement from the patient documented in the record
• c.Nothing, because the employer paid for the test
• d.A signed HIPAA authorization that names the employer✓

Releasing results to an employer is a disclosure outside treatment, payment, and health care operations, so it requires the patient's signed authorization identifying who may receive the information and what may be sent. A consent to treat permits care to be given; it does not permit disclosure to an outside party. A verbal agreement noted in the chart does not meet the written-authorization requirement, however well documented. Paying for a test buys the service, not the result, and the fact that the employer arranged and funded the examination gives it no independent right of access.

After a busy morning a technician realizes that a tracing she recorded an hour ago was saved under a different patient's name, and the record has already gone to the reading physician. What should the technician do?

• a.Report the error to the supervisor at once✓
• b.Wait and see whether the physician catches it
• c.Correct the name in the system and say nothing
• d.Note it on both charts at the end of the shift

A tracing filed under the wrong name puts one patient's data in front of a physician who will act on it for someone else, which is both a misidentification event and a disclosure, so it is escalated immediately rather than handled quietly. Prompt reporting lets the department pull the record from the reading queue before an interpretation is signed. Waiting for the physician to notice leaves a wrong result in an active chart. Fixing the name without telling anyone hides an event the facility has to track and may leave the mistaken interpretation in place, and holding the correction until the end of the shift gives the error hours to travel.

A patient's forearm is scraped by the EKG cart during transport, and an incident report is completed. What is the correct handling of that report?

• a.It is filed separately from the medical record✓
• b.It substitutes for charting the injury in the record
• c.It is scanned into the patient's chart as an addendum
• d.It is released to the patient with her other records

An incident report is an internal risk-management document, kept outside the medical record and outside what is released to the patient, which is why the chart must separately document the injury, the assessment, and the care given. Filing the report in the chart, or even referencing it there, can pull it into the released record and defeat the protection it carries in many states. Treating the report as a substitute for charting leaves the patient's own record silent about an injury that happened during care. The report is likewise not part of the designated record set a patient may request.

A technician forgets to chart a tracing performed at the end of her shift and returns the next morning to document it. What is the correct way to make that entry?

• a.Label it a late entry with the time of the tracing and of the entry✓
• b.Insert the note into the blank space left in the previous day's charting
• c.Chart it with the current date and time and no further comment
• d.Have the coworker now on duty enter it so the timing looks right

Documentation made after the fact is charted as a late entry, identified as such, carrying the date and time the care was actually delivered as well as the date and time of the entry. Writing it into blank space in the prior day's notes makes the record appear contemporaneous when it is not, which is falsification. Charting it under the current time alone puts the tracing on the wrong day and misrepresents the sequence of care. Asking another person to record work she did not perform is charting for someone else, which no facility permits.

A patient scheduled for a 12-lead speaks only Mandarin, and her teenage daughter offers to translate the technician's instructions. What should the technician do?

• a.Use the facility's qualified medical interpreter rather than the daughter✓
• b.Accept the daughter's help, because she knows her mother's history
• c.Ask the supervisor to move the tracing to an interpreter day
• d.Use gestures to demonstrate each step and proceed without help

Facilities receiving federal funds must provide language assistance at no cost to the patient, and qualified interpreters, including telephone and video services, exist for exactly this situation. Using a family member, particularly a minor, risks omitted or softened information and hands a child responsibility for a parent's medical communication. Rescheduling denies a patient timely care that an interpreter line could support within minutes. Gesturing through the procedure leaves the patient unable to ask a question, report discomfort, or meaningfully agree to what is being done.

A patient with moderate dementia becomes agitated and pushes the technician's hand away when chest electrode placement begins. Which approach is most appropriate?

• a.Work faster so the tracing is finished before the agitation increases
• b.Ask a family member to hold her arms still during the recording
• c.Explain each of the ten electrode positions in careful detail
• d.Approach calmly, use short simple sentences, and repeat them as needed✓

A patient with dementia processes speech slowly and reacts to tone and pace, so a calm approach, brief concrete sentences, one instruction at a time, and patient repetition are what allow the tracing to be obtained. Speeding up increases the agitation the technician is trying to avoid and raises the odds of motion artifact and a repeated study. Having a relative restrain her arms is physical restraint applied without an order and is not an acceptable way to complete a routine test. A detailed anatomical explanation adds information the patient cannot hold and tends to deepen the confusion.

A patient appears embarrassed when told that her chest must be exposed for the precordial leads. Which action best respects her modesty without compromising the tracing?

• a.Drape a gown or sheet over the chest between electrode placements✓
• b.Place the chest electrodes over the gown to avoid uncovering her
• c.Record the tracing with the curtain open so that a witness can observe
• d.Omit the two chest leads that call for the greatest exposure

Exposing only the small area being worked on and re-covering it as each electrode is placed protects modesty while still giving the skin contact the tracing depends on. Electrodes applied over clothing do not conduct and produce an unusable recording. Privacy is preserved by closing the curtain or door and limiting who is in the room, so recording in the open for the sake of a witness trades one problem for another; a chaperone can be present behind a closed curtain. Leaving out chest leads yields an incomplete study, and the missing leads are the ones that show the lateral wall.

A technician is about to record a routine 12-lead on a patient whose skin is intact, who has no drainage, and who is on no isolation precautions. Which statement describes correct glove use under standard precautions?

• a.Gloves are a matter of judgment for this contact, but hand hygiene before and after is not✓
• b.Gloves are worn for the entire study, and hand hygiene may be deferred while they are in place
• c.Gloves are put on only after the electrodes are placed and the lead wires have been attached
• d.Gloves are indicated here only if the chart documents a diagnosed bloodborne infection

Standard precautions call for gloves whenever contact with blood, body fluids, mucous membranes, or non-intact skin is anticipated. Placing electrodes on clean, intact skin does not meet that trigger, so glove use follows judgment and facility policy, while hand hygiene before and after every patient contact is required regardless. Gloves are not a substitute for hand hygiene, because hands can be contaminated through unseen defects and during removal. Waiting for a documented infection misreads standard precautions, which treat every patient's blood and body fluids as potentially infectious, and delaying gloves until after the leads are on would place them on after the contaminating contact has already happened.

A patient on contact precautions for Clostridioides difficile needs a bedside 12-lead. How should the technician handle equipment and hand hygiene for this study?

• a.Wear a gown and gloves, and use an alcohol-based hand rub after removing them as in other isolation rooms
• b.Leave the machine out in the corridor and run the lead wires in through the doorway to the bedside
• c.Bring the usual cart in, wear gloves, and then wipe the lead wires with an alcohol pad on the way out
• d.Take in only what is needed, use single-patient-use electrodes, wipe the machine with a bleach wipe, and wash with soap and water✓

C. difficile forms spores that alcohol does not kill and that alcohol-based rubs do not remove well, so hands are washed with soap and water and surfaces are wiped with an EPA-registered sporicidal product such as the facility's bleach wipe. Gown and gloves are correct for contact precautions, which is why the alcohol-rub answer is the tempting one, but the hand hygiene agent and the disinfectant are what change for spores. Carrying only necessary items into the room and using single-patient-use electrodes limits what has to be disinfected afterward. Running lead wires through a doorway does not keep the wires clean and breaks the containment the precautions exist to maintain.

A patient arriving for a treadmill stress test tells the technician that he has had chest pressure since early that morning and that it has not gone away. What should the technician do?

• a.Begin at the lowest workload and stop the treadmill if the pressure gets any worse during the first stage
• b.Hold the test, report the ongoing chest pressure to the supervisor and the covering clinician, and let them decide whether it proceeds✓
• c.Record a resting 12-lead, let the patient sit quietly, and start the protocol once the pressure has eased
• d.Note the reported pressure on the test worksheet and continue with the usual skin preparation

Chest pressure that is present at rest and ongoing raises the question of an acute coronary syndrome, which is a contraindication to exercise testing until a clinician has evaluated it. The technician does not diagnose the pain and does not decide whether the study is safe, so the finding goes to the supervising physician or nurse before anything else happens. Starting at a low workload still exercises a patient whose symptoms may reflect unstable ischemia. Waiting for the pressure to ease or simply writing it on the worksheet leaves the decision with the person least qualified to make it.

While a patient is connected to a portable EKG machine, the technician feels a faint tingle on touching the machine's metal frame. What is the correct response?

• a.Stop the study, unplug the machine, and tell the supervisor about the tingle✓
• b.Finish the tracing quickly, then set the machine on a rubber mat before the next study
• c.Unplug the machine, finish the recording on battery power, and then return it to storage
• d.Keep recording without touching the frame and enter the tingle in the equipment log at shift end

A tingle from a chassis means current is leaking to surfaces that should be at ground potential, which points to a failed ground or damaged insulation. A patient wired to that machine is in the current path and cannot pull away, so the study stops, the machine comes off the line, and it is reported so biomedical engineering can test it. Switching to battery power may remove the mains fault path, but it keeps a machine with a known defect wired to a patient and then puts it back on the shelf untested, and a rubber mat under the machine does nothing about the chassis the technician is touching. Logging the problem at the end of the shift leaves a defective machine available for the next patient.

A patient stands up from the table after a 12-lead, says the room is spinning, and begins to sag toward the floor. What should the technician do first?

• a.Hold the patient upright under both arms and walk her the few steps back to the exam table
• b.Step out of the room to bring a wheelchair and a second staff member to lift the patient back onto the table
• c.Guide the patient down to the floor, protecting the head, and call out for help without leaving her✓
• d.Seat the patient in the nearest chair and notify the supervisor before anything else

A patient who is already going down cannot be held up by one person; guiding the fall to the floor while protecting the head converts an uncontrolled fall into a controlled one and protects the technician's back at the same time. Once she is down and flat, help can be summoned without leaving her unattended. Trying to walk a fainting adult back to the table risks a heavier fall and an injury to both people. Leaving the room for a wheelchair, or moving her to a chair and going to find someone, both abandon an unsteady patient at the moment she is most likely to strike her head.

A technician who has not been fit-tested for an N95 respirator is sent to record a 12-lead on a patient in an airborne infection isolation room. What should the technician do?

• a.Stay out of the room and tell the supervisor so a fit-tested technician can do the study✓
• b.Enter wearing a surgical mask and a gown, since the recording itself takes only a few minutes
• c.Take any N95 from the supply cart and hold it firmly against the face during the recording
• d.Ask the nurse whether the patient can be brought to the hallway for the tracing

Respiratory protection requires a medical evaluation, training, and fit testing before a worker wears an N95, because an unfitted respirator leaks around the seal and gives false confidence. A technician who has not been fit-tested does not enter an airborne isolation room, and the study is reassigned to someone who has been. A surgical mask is not a respirator and does not filter fine airborne particles. Pressing an untested N95 to the face does not produce a seal, and moving the patient out of a negative-pressure room to avoid the problem exposes everyone in the corridor.

During a code, the defibrillator operator calls for everyone to clear the bed immediately before the shock is delivered. What is the reason for clearing at that moment?

• a.Movement at the bedside creates artifact that keeps the defibrillator from analyzing the rhythm
• b.Contact with the patient drains energy so that less of it reaches the heart muscle
• c.Standing back keeps staff from being splashed by the conductive gel used on the pads
• d.Current would travel through anyone in contact with the patient or the bed frame✓

The shock is a current that follows every available conductive path, so a hand on the patient, on the bed rail, or on a wet sheet puts a rescuer in that path and can produce a serious shock. Artifact from movement is a real problem, but that is why the operator calls a clear during the analysis pause on an automated device, not at the instant of discharge. Energy loss to a bystander is not the concern being managed by the clear command, and gel splash is not a hazard that would justify stopping compressions. The clear is called, the operator looks at the patient and the bed, and only then is the shock delivered.

A monitored patient has a temporary transvenous pacing wire and a central venous catheter in place. Why does this patient need extra electrical precautions?

• a.Metal pacing wires pick up interference that can make the displayed rhythm resemble ventricular fibrillation
• b.Fluid inside the central catheter conducts leakage current from the bedside outlets back into the monitor
• c.A pacing wire raises the energy a defibrillator must deliver before the shock reaches the heart muscle
• d.A conductor touching the heart lets tiny leakage currents bypass the skin and reach the myocardium✓

Intact skin has high resistance and spreads current over a wide area, which is why a person can touch a small leakage current and feel nothing. A pacing wire or a fluid-filled catheter that ends at or near the heart removes that protection, so a current far below the level anyone could feel can concentrate on the myocardium and provoke fibrillation. This is the microshock hazard, and it is why exposed wire ends are insulated and handled with gloves. Interference can indeed mimic fibrillation on a display, but that is an artifact problem rather than a reason for electrical precautions, and neither the catheter fluid nor the pacing wire changes the energy a defibrillator must deliver.

The power cord of an EKG machine ends in a three-prong plug. What does the third prong accomplish?

• a.It routes excess current away from the patient cable and into the machine's internal filtering circuits
• b.It bonds the chassis to ground so fault current returns there rather than through a person✓
• c.It supplies the additional voltage the recorder and the thermal print head draw during a tracing
• d.It keeps the plug from working loose from the outlet during a bedside study

The third prong is the equipment grounding conductor. It ties the metal chassis to earth ground, so if a hot conductor contacts the frame the fault current flows harmlessly to ground and trips the breaker instead of passing through whoever touches the machine. It carries no current in normal operation and supplies no voltage to the recorder or the print head, both of which run from the two current-carrying conductors. It also has no mechanical role in retaining the plug, which is why an adapter that defeats the ground pin is a real hazard rather than a convenience.

A patient completed a 24-hour Holter and her diary records no symptoms, because the palpitations she is being investigated for happen roughly once a week. Which statement about the next step is accurate?

• a.Another 24-hour Holter is simply repeated the following week, since this recorder captured no symptoms
• b.The physician may order a patient-activated event or loop recorder worn for weeks to catch symptoms days apart✓
• c.The study is reported as a normal result, because no symptoms occurred while the recorder was worn
• d.The technician reports the failed recording to the supervisor and rebooks the patient for a repeat study

A 24-hour Holter samples a single day, so a symptom that appears about once a week is unlikely to fall inside the recording window. Longer patient-activated event monitors and loop recorders are worn or implanted for weeks precisely to capture infrequent events, and selecting that study is the ordering physician's decision. Repeating another 24-hour recording has the same low yield as the first. The recorder did not fail and nothing needs to be escalated as an equipment problem, and an absence of captured symptoms is not the same finding as a normal heart rhythm.

A patient is being fitted with an ambulatory monitor that will be worn continuously for several days. How should each electrode site be prepared?

• a.Wipe each site with alcohol and apply the electrode while the skin is still damp, for better contact
• b.Apply a thin layer of skin lotion first so that the adhesive stays comfortable over several days of wear
• c.Omit preparation and tell the supervisor that some artifact is expected here
• d.Clip hair at the site, abrade the skin lightly, and let it dry before applying a fresh electrode✓

Skin preparation is what makes a multi-day recording readable: clipping rather than shaving avoids nicks that can become infected, light abrasion removes the dead outer cells that carry most of the skin's resistance, and a dry, oil-free surface lets the adhesive hold for days. Applying an electrode to skin still wet with alcohol traps solvent under the gel and loosens the adhesive as it evaporates. Lotion is the opposite of what is wanted, since it leaves an oily film that defeats both the adhesive and the electrical contact. Skipping preparation guarantees baseline wander and lost hours of data on a study the patient cannot easily repeat.

During the second stage of a treadmill stress test, the patient's systolic blood pressure has fallen about 15 mmHg below the resting value even though the workload has increased. What should the technician do?

• a.Repeat the blood pressure at the next stage and continue the protocol if that reading is higher
• b.Stop the test, notify the supervisor and the covering clinician at once, and keep monitoring rhythm and pressure in recovery✓
• c.Slow the treadmill to a walking pace for two minutes and then resume the protocol from that stage
• d.Continue the stage as ordered, because systolic pressure normally falls as the exercise workload rises

Systolic pressure is expected to rise as workload rises. A fall below the resting value during increasing exercise suggests the heart cannot raise its output against the demand and is a recognized indication to terminate the test, so the treadmill stops and the supervising clinician is told immediately rather than at the end. Monitoring continues into recovery, because rhythm changes and ischemic changes often appear after exercise stops. Waiting for the next stage, or slowing the belt and then resuming, keeps a patient exercising through the very finding that says to stop.

A patient has finished the exercise portion of a stress test and the treadmill belt has stopped. What does monitoring during the recovery period require?

• a.Recording ends when the belt stops, and the patient waits in the reception area until discharge
• b.Recovery tracings are recorded only for the patients who reported symptoms during the exercise stages
• c.The patient stays monitored until heart rate, blood pressure, and the EKG return toward baseline✓
• d.Monitoring stops once the heart rate drops below the target rate calculated for the patient's age

Recovery is part of the test, not the end of it. Ischemic ST changes and exercise-induced arrhythmias frequently appear or persist after exercise stops, and hypotension and fainting are most likely in the first minutes off the treadmill, so electrodes and the blood pressure cuff stay on and readings continue until heart rate, pressure, and the tracing approach the patient's baseline. Removing the leads when the belt stops throws away the segment most likely to show the abnormality. Recording recovery only for symptomatic patients misses silent ischemia, and dropping below the target heart rate says nothing about whether pressure or the ST segments have recovered.

A technician has to move a heavy portable EKG machine into a room and then help turn a patient in bed. Which approach best protects the technician from injury?

• a.Reach across the bed and draw the patient toward the far rail in one smooth motion
• b.Lift with the arms and shoulders while the knees stay straight and the feet stay together
• c.Raise the bed toward waist height, keep the feet apart, bend at the knees, and push the machine rather than pull it✓
• d.Turn at the waist to swing the machine into position instead of stepping around it

Sound body mechanics keep the load close, the base of support wide, and the work near waist level, so the large muscles of the legs do the lifting and the spine stays neutral. Pushing a wheeled machine uses body weight and is easier on the back than pulling it. Reaching across a bed puts the load far from the technician's center of gravity and is a common cause of back strain, which is why a turn is done from the near side or with a second person. Keeping the knees locked while lifting with the arms and twisting at the waist under load are the two motions most often behind lifting injuries.

A technician with a fever and a productive cough is assigned to record a 12-lead on a neutropenic patient in a protective environment room. What should the technician do?

• a.Enter wearing a surgical mask and gloves and keep the visit as brief as the study allows
• b.Record the tracing while standing at arm's length from the patient's head the whole time
• c.Report the symptoms to the supervisor and ask to be reassigned away from this patient✓
• d.Delay the study until the end of the shift and clean the machine first

A protective environment exists to keep organisms away from a patient whose neutrophil count leaves almost no defense, and a staff member with fever and a productive cough is exactly the exposure it is designed to exclude. Reporting the symptoms so the assignment can be changed protects the patient and follows the occupational health policy that governs working while ill. A surgical mask reduces droplet spread but does not make a febrile, coughing worker safe for a neutropenic patient, and no working distance is safe when electrodes must be placed on the chest. Postponing the study to the end of the shift changes only the hour, not the risk the technician brings into the room.

While removing electrodes from a patient with a bleeding puncture site, a technician gets a splash of blood in one eye. What is the immediate action?

• a.Flush the eye at an eyewash station with water for at least 15 minutes, then report the exposure✓
• b.Blot the eye with gauze, finish the study, and rinse at the sink once the patient has left the room
• c.Notify the supervisor and complete the exposure report form before rinsing the eye
• d.Rinse the eye briefly with sterile saline and carry on with the next scheduled patient

A mucous membrane exposure is decontaminated first, and the standard first aid is copious flushing with water or saline at an eyewash station for a sustained period, on the order of 15 minutes. Reporting follows immediately afterward so that the source patient can be evaluated and post-exposure prophylaxis considered within the window in which it works, but paperwork does not come before flushing. Blotting with gauze spreads rather than removes the blood and delays irrigation for the length of a study. A few seconds of saline is not irrigation, and continuing to the next patient skips the reporting that makes any later treatment or claim possible.

The code team has arrived and taken over the resuscitation of a monitored patient. How can the EKG technician best help while the code continues?

• a.Announce a formal rhythm interpretation and tell the team which drug should be given
• b.Take the pads from the defibrillator and place them while compressions are in progress
• c.Run rhythm strips, note the times of events, and keep the tracings for the record✓
• d.Leave and ask the supervisor which tasks are permitted during a code

Once the code team is present, the technician contributes within the certified scope: producing and labeling rhythm strips, recording the times of rhythm changes and interventions, and fetching supplies. That documentation is genuinely useful and is work the team cannot do while managing the airway and compressions. Calling the monitor for the team is ordinary practice, but announcing a formal interpretation and telling the team which drug to give converts that reading into a treatment decision, which a CET is not credentialed to make. Applying defibrillator pads belongs to the team members trained and authorized to defibrillate. Walking out of an active code to ask what is allowed removes a trained pair of hands at the worst possible moment.

A portable EKG machine is being set up in a crowded patient room, and the nearest wall outlet sits behind the bed. What is the correct way to power the machine?

• a.Plug it into a hospital-grade wall outlet, or run the study on the machine's own battery✓
• b.Plug it into the multi-outlet power strip that already serves the infusion pumps and the bed
• c.Run a household extension cord under the bed so that the outlet behind it can be reached easily
• d.Join a second power strip to the first one so that the cord will reach the machine

Equipment used in the patient care vicinity is plugged directly into a hospital-grade receptacle, and a machine with a charged battery can simply be run on battery power when no suitable outlet is within reach. Loading a portable machine onto a power strip that is already carrying pumps and a bed adds to a shared load and to a shared point of failure, and daisy-chaining one relocatable power tap into another is prohibited in patient care areas for that reason. A household extension cord is not built for this service, and running it under a bed exposes it to crushing and turns it into a trip hazard. Convenience does not justify adding a failure point between the machine and the wall.

Which layer of the heart wall is continuous with the visceral layer of the pericardium?

• a.The endocardium, the smooth inner lining of the chambers
• b.The parietal pericardium, the sac's outer serous layer
• c.The fibrous pericardium, anchored to the diaphragm
• d.The epicardium, the outer layer of the heart wall✓

The visceral layer of the serous pericardium lies directly on the surface of the heart, and that same sheet is the epicardium, the outermost of the three heart wall layers. The endocardium is at the opposite end of the wall, lining the chambers and valves on the inside. The parietal serous layer is the sheet that faces the epicardium across the pericardial space rather than being part of the heart wall. The fibrous pericardium is the tough outer sac that anchors to the diaphragm and great vessels and is not a heart wall layer at all.

Depolarization leaving the sinoatrial node reaches the left atrium chiefly by way of which structure?

• a.Bachmann's bundle, an interatrial conduction tract✓
• b.The two divisions of the bundle of His
• c.The anterior internodal tract, ending at the AV node
• d.The coronary sinus, along the posterior wall

Bachmann's bundle is the interatrial band that carries the impulse from the right atrium across to the left atrium, which is why the P wave represents both atria depolarizing nearly together. The internodal tracts also leave the sinoatrial node, but they carry the impulse down the right atrium toward the AV node rather than across to the left atrium. The bundle of His sits below the AV node and serves the ventricles, so it plays no part in atrial spread. The coronary sinus is a venous channel, not a conduction pathway.

In the large majority of adults, the atrioventricular node is supplied by a branch of which artery?

• a.The left anterior descending artery, which feeds the septum
• b.The left circumflex artery, which supplies the lateral wall
• c.The right coronary artery, in most adult hearts✓
• d.The left main coronary artery, before it branches out

Most people have a right-dominant coronary circulation, and in those hearts the AV nodal artery branches from the right coronary artery. That anatomy explains why an inferior wall infarction so often comes with AV nodal block and a slow junctional rhythm. The circumflex supplies the AV node only in the minority of hearts that are left-dominant, which makes it a reasonable but less common answer. The left anterior descending artery supplies the anterior wall, the front of the septum, and much of the bundle branches, while the left main is only a short trunk that divides almost immediately.

The left anterior descending artery is the main blood supply to which regions?

• a.The lateral left ventricular wall and the left atrium
• b.The inferior left ventricular wall and the AV node
• c.The anterior left ventricular wall and the septum✓
• d.The right ventricle and the right atrial wall

The left anterior descending artery runs down the front of the heart in the anterior interventricular groove and feeds the anterior wall of the left ventricle plus the front two thirds of the interventricular septum. Because much of both bundle branches sits in that septum, a blockage there can produce a bundle branch block as well as anterior wall damage. The lateral wall and the left atrium belong mostly to the circumflex, and the inferior wall with the AV node belongs to the right coronary artery in most hearts. The right ventricle and right atrium are also right coronary territory.

At which moment in the cardiac cycle does the aortic valve open?

• a.When left ventricular pressure exceeds aortic pressure✓
• b.When the left atrium contracts to top off the ventricle
• c.When the ventricles relax and chamber pressure falls off
• d.At the same instant the mitral valve opens

A semilunar valve is pushed open by pressure from behind it, so the aortic valve opens only once the contracting left ventricle has built up a pressure higher than the pressure in the aorta. Atrial contraction adds the last portion of filling while the aortic valve is still shut, so that moment is far too early. Falling ventricular pressure during relaxation is what lets the aortic valve snap closed, which is the opposite event. The mitral valve opens during filling, when the aortic valve is closed, so the two cannot open together.

The absolute refractory period of the ventricles covers which portion of the tracing?

• a.The PR segment, while the impulse waits at the AV node
• b.The downslope of the T wave into the TP segment
• c.The QRS complex through the peak of the T wave✓
• d.The P wave, while the atria depolarize

Ventricular cells cannot be restimulated from the start of the QRS until roughly the peak of the T wave, no matter how strong the stimulus, and that span is the absolute refractory period. The downslope of the T wave is the relative refractory period, where a strong enough stimulus can capture partially recovered tissue. The PR segment reflects the delay at the AV node before the ventricles have depolarized at all. The P wave is atrial depolarization and says nothing about ventricular recovery.

A premature ventricular beat lands on the downslope of the preceding T wave. Why is that timing dangerous?

• a.The ventricles have fully recovered, so the beat lands with extra force
• b.Recovery is uneven, so the beat can trigger fibrillation✓
• c.The T wave is where the atria repolarize, so atrial filling is lost
• d.The AV node is refractory then, so the beat cannot reach the ventricles

The downslope of the T wave is the relative refractory period, when some ventricular cells have recovered and others have not, and a stimulus arriving into that patchwork can start a chaotic reentrant rhythm such as ventricular tachycardia or ventricular fibrillation. This is the R on T phenomenon, and it is a finding a technician reports promptly rather than interprets. Full recovery of the ventricles happens later, after the T wave has ended, so the idea of a merely forceful beat misses the hazard. Atrial repolarization is buried inside the QRS complex, not in the T wave, and a ventricular beat by definition arises below the AV node and does reach the ventricles.

Rapid depolarization of a working ventricular muscle cell is produced mainly by which ion movement?

• a.Potassium moving out of the cell through slow channels
• b.Calcium entering slowly and sustaining the plateau phase
• c.Chloride shifting inward to balance the membrane charge
• d.Sodium rushing into the cell through fast channels✓

A working ventricular cell rests near negative 90 millivolts, and when threshold is reached the fast sodium channels open and sodium floods in, driving the steep upstroke that the QRS complex represents. Calcium is a genuinely tempting answer because slow calcium entry does maintain the plateau that keeps the cell contracting, and calcium rather than sodium drives the upstroke in pacemaker cells, but it is not what produces the rapid upstroke in working myocardium. Potassium leaving the cell is repolarization, the recovery phase seen as the T wave. Chloride shifts are not the driver of the cardiac action potential upstroke.

A technician obtains a 12-lead on a dialysis patient and sees tall, narrow, peaked T waves in most leads. Which electrolyte problem is classically associated with that pattern, and what is the technician's role?

• a.High potassium; reported to the nurse without interpreting the tracing✓
• b.Low potassium; reported to the nurse without interpreting the tracing
• c.Low calcium; reported to the nurse without interpreting the tracing
• d.High calcium; reported to the nurse without interpreting the tracing

Tall, narrow, peaked T waves are the classic tracing change described with an elevated potassium level, and a patient on dialysis is exactly the person in whom it is expected. A low potassium level does the opposite: it flattens the T wave and brings out a U wave. A low calcium level lengthens the QT interval and a high calcium level shortens it, and neither one peaks the T wave. The technician's role is the same whichever finding is on the tracing: acquire it, report it promptly to the nurse or provider, and leave the diagnosis and any explanation to the patient to the licensed staff.

Which electrolyte abnormality is classically associated with a prolonged QT interval?

• a.A high potassium level, which first peaks the T waves
• b.A high calcium level, which shortens the ST segment
• c.A low calcium level, lengthening the ST segment✓
• d.A high sodium level, which lifts the QRS amplitude

A low serum calcium level stretches out the ST segment, and because the QT interval is measured from the start of the QRS to the end of the T wave, that stretch shows up as a prolonged QT. An elevated calcium level does the reverse and shortens the ST segment and the QT, which is why it is a tempting near miss. An elevated potassium level is tied to tall peaked T waves and, at higher levels, a widening QRS rather than QT prolongation. Sodium levels have no classic QT signature, and in every case the technician reports the tracing and leaves the interpretation to the provider.

A provider performs carotid sinus massage during monitoring. The resulting vagal stimulation has which effect?

• a.It speeds the sinus rate and shortens conduction through the AV node
• b.It increases the force of ventricular contraction without changing rate
• c.It blocks conduction in the right and left bundle branches
• d.It slows the sinus rate and delays AV nodal conduction✓

Pressure on the carotid sinus stimulates baroreceptors, which raise parasympathetic outflow through the vagus nerve to the sinoatrial and atrioventricular nodes; the sinus rate falls and conduction through the AV node slows, often lengthening the PR interval or briefly unmasking atrial activity. Speeding the rate and shortening AV conduction is the sympathetic response, the opposite of what the vagus does. Vagal fibers have little effect on ventricular contractile force, so a pure inotropic change does not fit. The bundle branches are not under meaningful vagal control, so a maneuver like this does not create bundle branch block.

Preload is best described as which of the following?

• a.The resistance the ventricle must overcome to eject blood
• b.The share of ventricular volume ejected with each beat
• c.The contractile strength at a given fiber length
• d.The volume stretching the ventricle at end-diastole✓

Preload is the degree of stretch on the ventricular muscle just before it contracts, which in practice means the volume in the ventricle at the end of diastole. Within limits, more stretch yields a stronger contraction, the Frank-Starling relationship. Resistance to ejection is afterload, the closest and most commonly confused answer, and it is raised by conditions such as hypertension or aortic stenosis. Contractile strength independent of stretch is contractility, and the fraction of volume ejected is ejection fraction; both are separate measures.

Ejection fraction expresses which relationship?

• a.The volume of blood the left ventricle pumps in one minute
• b.The number of milliliters ejected by a single heartbeat
• c.The pressure the ventricle generates while it is contracting
• d.The share of end-diastolic volume the ventricle ejects each beat✓

Ejection fraction is stroke volume divided by end-diastolic volume, expressed as a percentage; a ventricle holding 120 milliliters at the end of filling and ejecting 66 milliliters has an ejection fraction of 55 percent. Volume pumped per minute is cardiac output, a different quantity built from rate and stroke volume. Milliliters ejected per beat is stroke volume itself, the numerator of the fraction rather than the fraction. Pressure generated during contraction is a measure of force, not of the proportion of the chamber emptied.

Before reaching the Purkinje network, the left bundle branch divides into which structures?

• a.The anterior and posterior internodal tracts
• b.The two divisions of the bundle of His
• c.The left anterior and left posterior fascicles✓
• d.The septal and marginal branches of the AV junction

The left bundle branch splits into a left anterior fascicle and a left posterior fascicle, which spread the impulse over the left ventricle before handing it to the Purkinje fibers; loss of one of them produces a hemiblock rather than a full bundle branch block. The internodal tracts are atrial pathways between the sinoatrial and atrioventricular nodes and never enter the ventricles. The bundle of His is the trunk that divides into the right and left bundle branches, so it sits above the split rather than being the product of it. The AV junction has no septal or marginal branches; those names belong to coronary arteries.

In an adult with normal anatomy, the apex of the heart sits at which location?

• a.In the second intercostal space at the right sternal border
• b.Just beneath the manubrium at the level of the second rib
• c.In the fifth intercostal space at the right midclavicular line
• d.In the fifth intercostal space, left midclavicular line✓

The heart lies in the mediastinum with about two thirds of its mass left of the midline, and the apex points down, forward, and to the left, landing at the fifth intercostal space in the left midclavicular line. That is the point of maximal impulse, and it is also the landmark for the V4 electrode. The mirror-image description on the right side is the same landmark on the wrong side of the chest, which is the trap in this item. The second intercostal space at the right sternal border marks the aortic area, and the region beneath the manubrium holds the great vessels rather than the apex.

Venous blood that has already perfused the myocardium returns to the circulation through which route?

• a.The pulmonary veins, which carry it to the left atrium
• b.The superior vena cava, with blood from the head and arms
• c.The coronary sinus, emptying into the right atrium✓
• d.The inferior vena cava, with blood from the abdomen and legs

The cardiac veins collect blood that has passed through the myocardium and drain into the coronary sinus, which lies in the posterior atrioventricular groove and empties directly into the right atrium. The venae cavae also deliver deoxygenated blood to the right atrium, but they carry blood returning from the body at large rather than from the heart muscle itself. The pulmonary veins carry oxygenated blood from the lungs into the left atrium, the opposite kind of blood and the wrong chamber. Coronary arterial filling, by contrast, occurs mainly during diastole.

While the sinoatrial node is functioning normally, why do the lower pacemaker sites not fire at their own intrinsic rates?

• a.Their pacemaker cells lose automaticity once a person reaches adulthood
• b.The AV node blocks retrograde impulses from traveling back down
• c.They fire only when the sympathetic nervous system stimulates them
• d.The faster sinus impulses reach and discharge them before they self-fire✓

Every latent pacemaker is drifting toward threshold, but the sinoatrial node reaches threshold first and its impulse arrives and depolarizes those sites before they can get there on their own; this is overdrive suppression, and it is why an escape rhythm appears only when the sinus node slows or fails. The lower sites keep their automaticity throughout life, which is exactly what makes an escape rhythm possible. Blocking impulses from returning upward does not explain why the lower sites stay quiet, since the issue is the downward impulse that keeps resetting them. Sympathetic stimulation modifies the rate of these sites but is not what starts them.

Automaticity refers to which property of cardiac cells?

• a.The ability to pass an impulse along to neighboring cells
• b.The ability to generate an impulse without outside stimulation✓
• c.The ability to respond to an electrical stimulus by depolarizing
• d.The ability to shorten and produce mechanical force

Automaticity is the capacity of certain cardiac cells to reach threshold and fire on their own, without any nerve or outside signal, and it is the property that lets the sinoatrial node, the AV junction, and the ventricles each serve as a pacemaker. Passing the impulse to neighboring cells is conductivity, the property that carries the wave through the myocardium once it has started. Responding to a stimulus by depolarizing is excitability, which is easily confused with automaticity because both describe an electrical response, but excitability requires a stimulus while automaticity does not. Shortening to produce force is contractility, the mechanical rather than electrical property.

In the classic three-stage model of a coronary event, which waveform change is linked to each stage?

• a.Ischemia produces pathologic Q waves, injury inverts the T wave, and infarction elevates the ST segment
• b.Ischemia produces T wave inversion, injury produces ST segment elevation, and infarction produces pathologic Q waves✓
• c.Ischemia produces ST segment elevation, injury produces a tall R wave, and infarction inverts the T wave
• d.Ischemia widens the QRS complex, injury depresses the ST segment, and infarction shortens the PR interval

The three stages are taught in the order the muscle is damaged. Muscle that is short of blood but not yet damaged repolarizes abnormally, which shows on the tracing as T wave inversion, often deep and symmetric. Muscle that is acutely damaged but still alive produces ST segment elevation in the leads sitting over that wall, and it is that finding which drives emergency treatment. Muscle that has died no longer conducts, so leads over it record pathologic Q waves. Pairing necrosis with T wave inversion or with a tall R wave reverses the sequence, and QRS widening with PR shortening belongs to conduction disorders rather than to this model.

A 12-lead shows Q waves at least 0.04 second wide in three neighboring leads. What does a pathologic Q wave indicate?

• a.Muscle that is short of blood but intact, so the Q waves clear once the chest pain is treated
• b.Muscle that has died and no longer conducts, a change that usually stays on the tracing for the rest of the patient's life✓
• c.Coronary spasm that shows up during an episode of pain and disappears between the episodes
• d.A normal septal finding that is expected in all twelve leads of a healthy adult heart

A Q wave is called pathologic when it is at least 0.04 second wide, which is one small box at 25 mm/sec, or deeper than about one third of the R wave that follows it. Dead myocardium is electrically silent, so an electrode over that area records depolarization traveling away from it and writes a deep initial downward deflection. Because scar does not recover, these Q waves generally persist for years, which is why they mark an old infarction as well as a new one and cannot be used to judge how recent the event was. Reversible ischemia and coronary spasm change the ST segment and T wave rather than carving a permanent Q wave. Small narrow Q waves are normal in a few leads, but not in all twelve.

Leads V1 and V2 sit directly over which part of the heart?

• a.The septum between the two ventricles✓
• b.The lateral wall of the left ventricle
• c.The inferior surface of the heart
• d.The posterior wall of the left ventricle

V1 sits in the fourth intercostal space at the right sternal border and V2 in the fourth intercostal space at the left sternal border, so both electrodes face the interventricular septum from the front. Changes limited to this pair are described as septal. The lateral wall is viewed from leads I, aVL, V5, and V6, and the inferior surface from II, III, and aVF, all of which sit well away from the sternum. The posterior wall has no electrode directly over it on a standard 12-lead and is inferred from mirror-image changes or recorded with added posterior leads.

Occlusion of the left circumflex artery most often produces changes in which group of leads?

• a.Leads II, III, and aVF, the inferior lead group
• b.Leads V1 through V4, the anteroseptal lead group
• c.Leads V1 and V2 alone, the septal lead pair
• d.Leads I, aVL, V5, and V6, the lateral group✓

In most people the left circumflex artery runs in the groove between the left atrium and left ventricle and supplies the lateral wall, so injury in its territory appears in the leads that face that wall: I and aVL high on the left side and V5 and V6 on the left chest. The inferior group is supplied by the right coronary artery in the large majority of adults. The anterior and septal leads follow the left anterior descending artery and its septal branches. Because the circumflex also supplies part of the posterior wall in many people, a technician may be asked to add posterior leads when the lateral leads are abnormal.

A patient with chest pain has tall R waves with flat ST depression in V1 and V2, plus ST elevation in II, III, and aVF. What should the technician anticipate next?

• a.Reversed arm electrodes, so the whole tracing is discarded and repeated once the limb leads are swapped back
• b.A possible posterior wall infarction, and a request for the posterior leads V7, V8, and V9 across the left side of the back✓
• c.Right ventricular involvement, checked by moving the V4 electrode across to the right side of the chest
• d.Anterior wall ischemia, checked by running the same 12-lead again after the patient has rested

No electrode on a standard 12-lead faces the posterior wall, so posterior injury is read as a mirror image in the leads on the opposite side of the chest: the ST elevation appears as ST depression in V1 and V2 and the deep Q wave appears as a tall R wave. Posterior leads placed across the left side of the back give a direct view and confirm the finding. Right ventricular involvement is a real possibility with an inferior pattern and is checked with a right-sided chest lead, but it does not explain tall R waves in V1 and V2. Reversed arm electrodes distort the limb leads and leave the chest leads alone, so they cannot produce this picture. The technician reports the tracing at once and lets the provider decide which extra leads to order.

A patient describes chest discomfort that wakes her at about the same hour most nights and passes within a few minutes. A tracing captured during one episode showed ST elevation that had resolved by the time she reached the clinic. Which pattern does this fit?

• a.Stable angina, because the discomfort is predictable and brief
• b.Variant angina, from coronary spasm rather than from exertion✓
• c.Unstable angina, because the pattern has recently changed
• d.An evolving infarction, because the ST segment was elevated

Variant angina, also called Prinzmetal angina, comes from spasm of a coronary artery rather than from a fixed narrowing, so it strikes at rest and often at the same hour of the night, and the ST elevation it produces is transient and gone once the spasm relaxes. Unstable angina is the answer worth weighing, because it also occurs at rest and represents a change in pattern, but it usually shows ST depression or T wave inversion rather than elevation that comes and goes with the episode. Stable angina is provoked by exertion and relieved by rest, which does not fit discomfort that wakes a sleeping patient. An evolving infarction leaves ST elevation that persists and then evolves over hours rather than resolving in minutes. The technician records and reports what was captured and does not label the pattern on the tracing.

A tracing shows ST elevation in II, III, and aVF together with ST depression in I and aVL. How is the depression in I and aVL best described?

• a.A second blocked vessel supplying the high lateral wall, separate from the artery causing the elevation
• b.A reciprocal change, the same injury current recorded by leads that face the heart from the opposite side✓
• c.Digitalis effect, which drags the ST segment down into a sagging curve in the limb leads
• d.An artifact created by poor contact between the left arm electrode and the skin

An injured wall pushes the ST segment up in the leads sitting over it, and leads aimed at the heart from the far side record that same current heading away from them, which writes ST depression. Because I and aVL look at the heart from the high left side and II, III, and aVF look at it from below, those two groups are reciprocal to one another. A separate blockage is a real possibility when depression is deep or widespread, but the mirror pattern is expected with any inferior injury and does not by itself mean two vessels. Digitalis produces its sagging depression without ST elevation elsewhere, and a loose electrode would degrade the baseline rather than shift the ST segment in a matched pair of leads.

A patient who had an anterior myocardial infarction one month ago has deep Q waves in V3 and V4, ST segments back at the baseline, and shallow T wave inversion. Which description fits the tracing?

• a.An acute injury pattern that began within the past hour and is still developing
• b.A placement error, since V3 and V4 were set one interspace too high on the chest
• c.An evolved infarction, because the Q waves persist after the ST segment has returned to baseline✓
• d.A resolved infarction with a normal tracing, since the injured muscle has healed completely

A coronary event evolves in a fairly consistent order: tall T waves and ST elevation come first, Q waves appear over hours to days, and the ST segment settles back to the baseline over the following days to weeks while the T waves stay inverted for a while. Q waves are the part that does not fade, so a tracing with Q waves, a flat ST segment, and residual T wave inversion fits an event that happened some time ago. Acute injury would still show ST elevation, which this tracing does not. Calling the tracing normal ignores the Q waves, which record scar that will remain, and electrodes placed an interspace too high alter R wave progression rather than carving deep Q waves in a patient with a known infarction.

A technician finishes a 12-lead on a patient with chest pain and sees 2 mm of flat ST depression across V4, V5, and V6. What is the correct action?

• a.Tell the patient the tracing shows a partly blocked coronary artery
• b.Repeat the tracing after the patient has rested for thirty minutes
• c.Write lateral wall ischemia in the interpretation field of the report
• d.Report the finding to the nurse or provider without delay✓

ST depression and T wave inversion suggest that muscle is short of blood, a finding that can change quickly, so the tracing goes to a licensed clinician right away rather than waiting in a queue. The technician acquires, recognizes, and reports; naming a wall and a diagnosis on the report is interpretation and sits outside the certified technician's scope. Explaining the tracing to the patient is outside that scope as well, and it can frighten a patient over a finding the provider may read differently. Waiting half an hour to repeat the tracing delays care for a patient who may be infarcting.

A patient reports sharp chest pain that eases on leaning forward. The 12-lead shows ST elevation in nearly every lead with PR segment depression and no reciprocal depression. Which condition is classically linked to that pattern?

• a.An extensive anterior infarction that has spread across several coronary territories
• b.Left ventricular hypertrophy from years of poorly treated high blood pressure
• c.A high potassium level in a patient whose kidney function has fallen off
• d.Acute pericarditis, an inflammation of the sac that surrounds the heart✓

Inflammation of the pericardium touches the surface of the heart in every direction, so the ST elevation is spread across leads from many different angles instead of clustering in one arterial territory, and because no single wall is injured there is no mirror-image depression opposite it. Depression of the PR segment and pain that eases when the patient sits up and leans forward fit the same picture. An infarction follows the path of one artery, so its elevation is grouped and usually has reciprocal depression somewhere. Hypertrophy raises voltage and shifts the ST segment in the leads with the tallest complexes, and a high potassium level shows peaked T waves. The technician recognizes the pattern, reports it promptly, and leaves the diagnosis to the provider.

Which P wave change is classically associated with enlargement of the right atrium?

• a.A wide, notched P wave lasting longer than 0.12 second in lead II
• b.A P wave that changes its shape from one beat to the next in lead II
• c.A P wave inverted in lead II ahead of a narrow QRS
• d.A tall, peaked P wave of 2.5 mm or more in lead II✓

The first half of the P wave is written by the right atrium and the second half by the left. When the right atrium is enlarged its portion grows taller rather than longer, producing a pointed P wave of at least 2.5 mm in the inferior leads, a shape often reported with lung disease that raises pressure on the right side of the heart. A wide, notched P wave beyond 0.12 second reflects the left atrium taking extra time to depolarize and is the classic left-sided finding, which makes it the closest competitor here. A P wave inverted in lead II points to an impulse starting near the AV junction and traveling backward through the atria, and a P wave that keeps changing shape points to a pacemaker site that keeps moving.

Every complex on a finished 12-lead looks unusually small and is hard to measure. What should the technician check first?

• a.Whether the patient's body build accounts for the small complexes
• b.Whether the gain is set at 10 mm/mV rather than at half standard✓
• c.Whether the paper speed was left at 50 mm/sec instead of 25 mm/sec
• d.Whether the limb electrodes were placed on the torso

The standardization mark printed at the start of the tracing should stand 10 mm tall, which is the 10 mm/mV setting; if the machine was switched to half standard, every complex is recorded at half its true height and a normal heart appears to have low voltage. Checking that mark takes seconds and is done before anything is reported. Paper speed changes how wide the complexes look, not how tall, so 50 mm/sec would stretch the tracing rather than shrink it. A heavy chest wall, air trapping in the lungs, and fluid around the heart are genuine causes of small complexes, but they are considered after the machine settings have been ruled out, and torso limb placement alters the tracing without shrinking every lead uniformly.

A hypothermic patient's tracing shows a distinct positive deflection at the junction between the QRS complex and the ST segment. What is that deflection called?

• a.A delta wave from an accessory conduction pathway
• b.A U wave that follows the T wave in hypokalemia
• c.An Osborn wave at the J point of the complex✓
• d.A pathologic Q wave from an old infarction

The point where the QRS complex ends and the ST segment begins is called the J point, and in a cold patient an extra rounded hump appears there, named the Osborn wave after the physician who described it. It usually keeps company with a slow rate, lengthened intervals, and a wandering baseline from shivering, so the technician warms and steadies the patient before repeating the tracing. A delta wave sits at the start of the QRS as a slurred upstroke rather than at its end, and it shortens the PR interval. A U wave arrives after the T wave, well past the J point, and is linked to a low potassium level.

A rhythm strip shows a narrow vertical spike immediately before each wide QRS complex, and every spike is followed by a complex. What does this most likely represent?

• a.A ventricular pacemaker that is capturing, which the technician documents on the tracing before it goes to the provider✓
• b.Interference at 60 cycles per second from an electrical device close to the patient's bed
• c.A premature ventricular complex arising from an irritable focus below the AV junction
• d.Muscle tremor artifact from a patient who is shivering throughout the recording

An implanted pacemaker fires a brief pulse that the machine records as a thin vertical line, and when that line is followed each time by a QRS complex the pacemaker is capturing, meaning the ventricle answers every stimulus. The complex is wide because the impulse starts in the ventricle and spreads through muscle rather than down the normal conduction pathway. Noting the device is part of the record, since a provider reading the tracing without that note may mistake the paced complexes for a ventricular rhythm. Sixty-cycle interference lays a steady fine ripple over the entire tracing rather than a single spike tied to each beat, muscle tremor produces an irregular fuzzy baseline, and a premature ventricular complex is early and occasional rather than present ahead of every beat.

A patient who takes digoxin has a 12-lead with scooped, downsloping ST depression in the lateral leads and a short QT interval. What does that pattern most likely represent?

• a.Ischemia of the inner layer of the lateral wall of the left ventricle
• b.Digoxin toxicity, which means the technician holds the patient's next dose
• c.The expected digoxin effect, which is reported and not interpreted✓
• d.A low potassium level producing a U wave after each T wave

Digoxin at ordinary doses changes repolarization, and the classic footprint is a sagging, scooped ST depression with a shortened QT interval, seen most easily in the leads with tall R waves. This is a drug effect rather than a sign of poisoning, and it can appear in a patient whose blood level is entirely normal, so the technician notes the finding and the medication and lets the provider read it. True toxicity announces itself with rhythm disturbances rather than with the scooped ST segment, and holding a dose is a decision for a licensed clinician, not the technician. Subendocardial ischemia usually depresses the ST segment in a flat or downsloping line without shortening the QT interval, and a low potassium level adds a U wave after the T wave instead.

Which item in a patient's history is a non-modifiable risk factor for coronary artery disease?

• a.Type 2 diabetes that is controlled with an oral medication
• b.A father who had a myocardial infarction at age forty-six✓
• c.An LDL cholesterol level above the patient's treatment goal
• d.Cigarette smoking of about half a pack on most days

Risk factors are sorted by whether treatment or behavior can change them. Age, sex, and inherited tendency cannot be changed, so a close blood relative who had an early coronary event stays on the list for life and is weighed more heavily when the relative was young. Diabetes is the trap in this set, because the diagnosis is permanent while the risk it carries is very much modifiable through glucose control, which is why it is grouped with the treatable factors. Cholesterol and smoking are the textbook modifiable factors, since both respond to treatment or to stopping. A technician does not counsel the patient about these findings but does record an accurate history.

A 74-year-old woman with long-standing diabetes is short of breath and nauseated and denies any chest pain. The provider orders a 12-lead. What is the best reason for that order?

• a.Diabetes alters the shape of the QRS complex, so a baseline tracing is needed
• b.Nausea on its own is the most common first symptom of a coronary event
• c.Older adults, women, and people with diabetes often infarct without chest pain✓
• d.Shortness of breath points away from the heart, and the tracing documents that

The crushing substernal pain that textbooks describe is the typical presentation, not the only one. Older adults, women, and people who have had diabetes for years frequently present instead with shortness of breath, fatigue, nausea, sweating, or pain in the back, jaw, or upper abdomen, and long-standing diabetes can blunt the nerve signals that would otherwise produce pain at all. That is why a tracing is obtained on this patient rather than waiting for a symptom she may never report. Nausea alone is not the most common opening symptom of a coronary event, shortness of breath does not steer suspicion away from the heart, and diabetes does not reshape the QRS complex.

A patient scheduled for a routine 12-lead has an implanted cardioverter-defibrillator under the skin of the left upper chest. How should the technician proceed?

• a.Cancel the study, because current from the EKG machine can damage an implanted device
• b.Acquire the tracing as ordered, shifting an electrode slightly if one lands on the generator, and note the device on the record✓
• c.Move all six chest electrodes to the right side of the chest to keep them clear of the device
• d.Wait until the device has been turned off in the clinic and then record the tracing

A 12-lead machine only listens; it sends no current into the patient, so recording a tracing is safe for someone with an implanted defibrillator or pacemaker. The electrode positions do not change, although one that would sit directly over the hard bulge of the generator can be moved a small distance so it lies flat on skin and makes clean contact. The presence of the device belongs on the record, because pacing spikes and the wide complexes that follow them are easy to misread when the reader does not know a device is there. Mirroring the chest leads to the right side records an entirely different set of views and would misrepresent the patient, and asking for the device to be deactivated exposes the patient to risk for no benefit.