What does ventricular depolarization correspond to in an EKG?

Ventricular depolarization is reflected in an EKG by the QRS complex. This phase occurs when the electrical impulse travels through the ventricles, causing them to contract, which is critical for effective blood pumping from the heart.

During this process, the heart's electrical system propagates an action potential that leads to the muscle fibers of the ventricles depolarizing, and this produces the large, sharp deflections seen in the QRS complex on the EKG. This is a pivotal moment in the cardiac cycle, as it directly leads to ventricular contraction and ejection of blood into the aorta and pulmonary artery.

In contrast, the P wave represents atrial depolarization, which is the electrical activity that triggers the contraction of the atria. The T wave indicates ventricular repolarization, which is when the ventricles recover after contraction. The P-R interval indicates the time between atrial depolarization and ventricular depolarization, but it does not represent the depolarization process itself. Each of these aspects plays a distinct role in the overall rhythm and function of the heart, but it is the QRS complex that specifically correlates with ventricular depolarization.