CAMRT Radiography Practice Exam 2025 - Free Radiography Practice Questions and Study Guide

The component of the ECG that reflects atrial depolarization is the P wave. During the cardiac cycle, the P wave represents the electrical activity associated with the depolarization of the atria, which is the phase where the atrial muscles contract to push blood into the ventricles. This initial electrical impulse originates from the sinoatrial (SA) node and spreads through the atria, leading to the contraction of the atrial muscles.

The other components of the ECG serve different purposes: the T wave represents ventricular repolarization, the QRS complex corresponds to ventricular depolarization, and the J point marks the junction between the end of the QRS complex and the beginning of the T wave, indicating the moment when ventricular depolarization ends and ventricular repolarization begins. Understanding these components is vital for interpreting an ECG and recognizing the electrical activity of the heart.