What does the P wave represent on an EKG?

The P wave on an EKG represents atrial depolarization. This is a crucial phase in the cardiac cycle where the electrical impulse from the sinoatrial (SA) node spreads through the atria, causing them to contract and push blood into the ventricles. The P wave is the first deflection on the EKG waveform and is typically small and rounded, reflecting the relatively small muscle mass and electrical activity of the atria compared to the ventricles.

Understanding the significance of the P wave is essential in interpreting EKGs, as it indicates that the heart's electrical system is functioning correctly and that the atria are contracting at the appropriate time in the cardiac cycle. Abnormalities in the P wave can suggest issues such as atrial enlargement or other atrial pathologies.