Rhythm InterpretationQuestion 2 of 100
What is the normal duration of the QRS complex in an adult?
a.Less than 0.12 second
b.0.12 to 0.20 second
c.0.20 to 0.36 second
d.Greater than 0.44 second
Explanation
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.
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Related questions on this topic
- 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?
- 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 patient has an irregular rhythm. The technician counts 11 QRS complexes in a six-second strip. What is the approximate heart rate?
- What electrical event does the P wave represent on an EKG tracing?
- 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?
- Using the 1500 method, a technician counts 20 small boxes between two consecutive R waves on a regular strip. What is the heart rate?
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