TCRN Practice Exam 2026 – Complete Prep for Your Test

The correct choice indicates the QRS complex, which is a key component of the electrocardiogram (ECG) and is specifically associated with the depolarization of the right and left ventricles.

During the cardiac cycle, depolarization refers to the process where the heart's muscle cells become activated and contract. The QRS complex occurs after the P wave (which represents atrial depolarization) and is followed by the T wave (which represents ventricular repolarization). The QRS complex is characterized by its sharp, tall peaks and represents the electrical activity that leads to the contraction of the ventricles, which is essential for effective blood pumping to the lungs and the rest of the body.

In contrast, the P wave is linked to the depolarization of the atria, and the T wave signifies the recovery phase after the ventricles have contracted. The Q wave is a part of the QRS complex itself but does not encapsulate the entire process of ventricular depolarization, which includes not only the Q wave but also the R and S waves that follow. Therefore, the QRS complex as a whole accurately captures the essential event of ventricular depolarization crucial to understanding cardiac function.