What does the P wave represent in an EKG?

The P wave in an electrocardiogram represents atrial depolarization, which is the electrical activity that leads to the contraction of the atria. When the heart's sinoatrial (SA) node generates an impulse, this impulse spreads through the atria, causing them to depolarize. The upward deflection seen in the P wave indicates this depolarization, which is essential for the initiation of the cardiac cycle, as it allows the atria to contract and push blood into the ventricles.

Understanding this function of the P wave is crucial for interpreting the overall rhythm and functionality of the heart as it provides insights into atrial electrical activity and can help identify potential abnormalities such as atrial enlargement or various types of atrial arrhythmias.