NHA EKG Technician (CET) — All Questions

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.