EPU Electrophysiology Practice Exam

Which of the following is a normal QRS duration value?

<120 ms >200 ms 40-60 ms 150-170 ms

Correct Answer:

<120 ms

Explanation:

QRS duration shows how long ventricular depolarization takes on the ECG. In a healthy heart, this happens quickly, so the QRS complex is narrow. The normal upper limit is about 120 milliseconds (0.12 seconds), with many sources citing 60–100 ms as typical. Therefore, a QRS duration shorter than 120 ms is considered normal. When the QRS duration exceeds 120 ms, it signals delayed intraventricular conduction, such as a bundle branch block or other conduction abnormalities. Values like 150–170 ms or over 200 ms clearly indicate abnormal conduction. A value of 40–60 ms is shorter than typical for adults and is not regarded as the normal range in standard ECG interpretation.

Access more questions from this quiz

Continue to EPU Electrophysiology Practice Exam for more practice questions and the full quiz experience.

Access More Questions