What physiological measure does end-systolic volume represent?

End-systolic volume is a crucial measure in understanding cardiac function as it represents the volume of blood that remains in the ventricles of the heart following contraction, specifically after the heart has completed systole. During systole, the heart contracts and pumps blood out into the circulatory system; however, not all the blood is expelled from the ventricles. The end-systolic volume quantifies this residual blood and can provide insights into the heart's efficiency, contractility, and overall health.

This measure is important because it helps determine the stroke volume, which is the amount of blood ejected with each heartbeat. By knowing both the end-diastolic volume (the volume of blood in the ventricles before contraction) and the end-systolic volume, you can calculate stroke volume and assess cardiac performance. Understanding end-systolic volume can also assist in diagnosing various heart conditions, as a higher than normal volume may indicate heart failure or other cardiac issues.