Which wave represents atrial depolarization on an ECG?

The P wave is the component of the electrocardiogram (ECG) that indicates atrial depolarization. In the context of cardiac electrical activity, depolarization refers to the process by which the heart muscle cells undergo a change in membrane potential, leading to contraction. The timing of the P wave corresponds to the moment when the electrical impulse from the sinoatrial (SA) node spreads through the atria, causing them to contract and push blood into the ventricles.

Understanding the role of the P wave is crucial for interpreting ECGs effectively. It clearly reflects the electrical activity associated with the atrial contraction cycle, and abnormalities in this wave can indicate various atrial issues, such as atrial enlargement or atrial fibrillation. Each ECG component serves a distinct purpose, and recognizing that the P wave is specifically tied to atrial activity allows healthcare professionals to diagnose and manage cardiac conditions more accurately.