In a normal electrocardiogram, the P-R interval represents:
A) atrial depolarization.
B) ventricular depolarization.
C) onset of atrial activation to onset of ventricular activity.
D) "electrical systole" of the ventricles.

Question

Quizplus · Accepted Answer

The P-R interval on an electrocardiogram represents the time from the onset of atrial activation to the onset of ventricular activity. This is measured from the beginning of the P-wave to the beginning of the QRS complex. Atrial depolarization is represented by the P-wave alone, and ventricular depolarization is represented by the QRS complex alone. The P-R interval reflects the delay between the activation of the atria and the activation of the ventricles, allowing time for the atria to contract and fill the ventricles before they contract.

In a Normal Electrocardiogram, the P-R Interval Represents