Certified Rhythm Analysis Technician (CRAT) Practice Exam 2026 - Free CRAT Practice Questions and Study Guide

The P wave on the ECG waveform represents atrial depolarization, which is the electrical activity that leads to the contraction of the atria. During this phase, the electrical impulse that originates in the sinoatrial (SA) node travels through the atria, causing them to contract and push blood into the ventricles. This depolarization appears as the P wave on the ECG tracing, which is typically positioned before the QRS complex.

Understanding the significance of the P wave is crucial for interpreting ECGs correctly, as it provides information about the atrial rhythm and function. In contrast, the other waveforms have distinct roles: the Q wave is part of the QRS complex and represents ventricular depolarization; the T wave signifies ventricular repolarization; and the R wave, being a component of the QRS complex, specifically represents the upward deflection associated with ventricular depolarization. Therefore, the P wave is uniquely associated with atrial depolarization and the resultant contraction of the atria.