What is the primary function of the P wave in heart rhythm?

The primary function of the P wave in heart rhythm relates to the electrical activity of the heart, specifically representing the depolarization of the atria. When the P wave occurs on an electrocardiogram (ECG), it indicates that the sinoatrial (SA) node has generated an electrical impulse that causes the atria to contract. This contraction results in the movement of blood from the atria into the ventricles.

The option indicating that the P wave initiates the electrical signal to the AV node captures the essential role of the P wave in the sequence of cardiac events. While it is accurate that the electrical signal travels from the SA node to the atrioventricular (AV) node, leading to the subsequent conduction through the ventricles, the function of the P wave is primarily to reflect this atrial depolarization event.

In essence, the P wave is crucial for ensuring the heart maintains its rhythmic and synchronized contractions.