Ejection fraction

Ejection fraction: The portion of blood that is pumped out of a filled ventricle as a result of a heartbeat. The heart does not eject all of the blood that is in the ventricle. Only about two-thirds of the blood is normally pumped out with each beat. That fraction is referred to the ejection fraction. The ejection fraction is an indicator of the heart's health. If the heart is diseased from a heart attack or another cardiac condition, the ejection fraction may fall, for example, to a third. Only a third of the blood in the ventricle (half the normal two-thirds) is pumped out. The heart is essentially half-normal (in this respect).