What is the primary event during late systole?

The primary event during late systole is rapid ventricular ejection followed by pressure normalization. At this phase of the cardiac cycle, the ventricles have contracted and are expelling blood into the aorta and pulmonary artery. This ejection is characterized by a rapid increase in ventricular pressure, which pushes blood out of the heart.

As late systole progresses, the ventricular pressures begin to decrease as the majority of the blood has already been ejected. This normalization of pressure is crucial as it prepares the heart for the subsequent diastole phase, where the ventricles will relax and fill with blood from the atria.

Understanding this process helps emphasize the transition between the two phases of the cardiac cycle and highlights the importance of pressure dynamics in the heart's function. The events in late systole are essential for maintaining effective blood flow and ensuring that the heart is ready for the next cycle.