CVS Practice Test 2025 – Complete Exam Preparation

The QRS complex represents the period of ventricular depolarization on an electrocardiogram (ECG). A normal duration of the QRS complex typically ranges from 0.06 to 0.10 seconds (60 to 100 milliseconds). This reflects the time it takes for the electrical impulse to travel through the ventricles and initiate their contraction.

Understanding this normal range is crucial because a duration outside of 0.05 to 0.10 seconds can indicate potential issues with the heart's electrical conduction system. For example, a prolonged QRS complex (greater than 0.10 seconds) may suggest a bundle branch block or other forms of ventricular conduction delay, whereas a very narrow complex could indicate normal conduction through the His-Purkinje system.

The other ranges provided in the choices exceed the normal duration significantly. Thus, Option A accurately represents the expected duration of a QRS complex in a healthy heart, making it the correct choice.