What does the ejection fraction indicate?

Ejection fraction is a critical measurement used to evaluate the efficiency and performance of the heart, particularly the ventricles. It is defined as the percentage of blood that is pumped out of the ventricles with each contraction. This percentage reflects the heart's ability to effectively pump blood throughout the body, which is essential for maintaining adequate circulation and oxygen delivery to tissues.

A healthy heart typically has an ejection fraction ranging from 55% to 70%, indicating that a significant portion of the blood within the ventricles is being utilized with each heartbeat. If the ejection fraction is lower than normal, it may suggest heart dysfunction, heart failure, or other cardiac issues, as the heart is not pumping effectively.

In contrast, options related to heart size, blood return to the heart, or heart rate do not convey the same specific insight into pumping efficiency as the ejection fraction does. Thus, "the percentage of blood pumped out of the ventricles with each heartbeat" accurately describes the significance and implications of the ejection fraction in cardiology.