Which part of the ECG corresponds to the depolarization of the atria?

The P wave in the electrocardiogram (ECG) represents the depolarization of the atria. During this phase of the cardiac cycle, the electrical impulses initiated by the sinoatrial (SA) node cause the atrial muscles to contract, pushing blood into the ventricles. The P wave is typically a small, upward deflection in the ECG trace, occurring just before the QRS complex, which signifies the depolarization of the ventricles.

Understanding the specific characteristics of the ECG waveform is essential for analyzing cardiac function. The P wave is crucial because it informs us about the electrical activity of the atria and indicates the initial step in the heart's contraction process. This knowledge is important in clinical settings, as abnormalities in the P wave can indicate atrial enlargement or other cardiac pathologies.