An ejection fraction related to the heart is the volumetric fraction of blood ejected from a ventricle or atrium with each contraction. An ejection fraction can also be used in relation to the gall bladder, or to the veins of the leg. Unspecified it usually refers to the left ventricle of the heart. EF is widely used as a measure of the pumping efficiency of the heart and is used to classify heart failure types. It is also used as an indicator of the severity of heart failure, although it has recognized limitations. From Wikipedia
