The QRS complex should not be wider than how long?

• A. 0.05 seconds
• B. 0.10 seconds
• C. 0.20 seconds
• D. 0.30 seconds

Answer: (B)

The QRS complex represents the depolarization of the ventricles in the heart and normally lasts between 0.06 seconds and 0.10 seconds. A QRS duration of more than 0.10 seconds indicates a delay in ventricular conduction, which could be due to a variety of issues, including bundle branch blocks or other conduction system disturbances.

The value of 0.10 seconds is significant since it is the upper limit of normal for the QRS duration. A duration exceeding this threshold usually warrants further investigation to determine the underlying cause of the prolonged QRS interval, as it may suggest pathologies that could affect the heart's electrical conduction system.

Longer durations, such as those exceeding 0.20 seconds or 0.30 seconds, are even more indicative of serious conduction disturbances, but the accepted limit for normal is 0.10 seconds. Therefore, recognizing that the QRS complex should not exceed 0.10 seconds is essential for accurate ECG interpretation and for identifying potential cardiac issues.