What does the P wave represent in an ECG?

The P wave in an electrocardiogram (ECG) represents atrial depolarization. This is the electrical activity that triggers the contraction of the atria, the upper chambers of the heart. During this phase, the electrical impulse generated by the sinoatrial (SA) node spreads through the atria, causing them to contract and pump blood into the ventricles.

Understanding the P wave is crucial for interpreting the overall heart function and rhythm. An abnormal P wave can indicate conditions such as atrial enlargement or atrial arrhythmias, making its identification essential for accurate diagnosis and treatment planning in cardiac care.