The QRS complex on an ECG tracing represents
A) atrial depolarization.
B) atrial repolarization.
C) ventricular depolarization.
D) ventricular repolarization.
E) ventricular contraction.

Question

Quizplus · Accepted Answer

The QRS complex represents ventricular depolarization, which is the electrical stimulation of the ventricles that leads to their contraction. The atria depolarize prior to the ventricles, but this is represented by the P wave on an ECG tracing, not the QRS complex. Ventricular repolarization occurs after the QRS complex, but is typically obscured by the T wave. Ventricular contraction is not directly represented on an ECG tracing, but occurs as a result of the ventricular depolarization represented by the QRS complex.

The QRS Complex on an ECG Tracing Represents