Ejection fraction

An ejection fraction (EF) related to the heart is the volumetric fraction of blood ejected from a ventricle or atrium with each contraction (or heartbeat). An ejection fraction can also be used in relation to the gallbladder, 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. The EF of the left heart, known as the left ventricular ejection fraction (LVEF), is calculated by dividing the volume of blood pumped from the left ventricle per beat (stroke volume) by the volume of blood present in the left ventricle at the end of diastolic filling (end-diastolic volume). LVEF is an indicator of the effectiveness of pumping into the systemic circulation. The EF of the right heart, or right ventricular ejection fraction (RVEF), is a measure of the efficiency of pumping into the pulmonary circulation. A heart which cannot pump sufficient blood to meet the body's requirements (i.e., heart failure) will often, but not always, have a reduced ventricular ejection fraction. In heart failure, the difference between heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) is significant, because the two types are treated differently.