The ejection fraction ( EF ) refers to the amount, or percentage, of blood that is pumped (or ejected) out of the ventricles with each contraction. This percentage, or EF number, helps your health care provider determine how your heart is functioning.
Heart failure is divided into two types based on ejection fraction, which is the proportion of blood pumped out of the heart during a single contraction. Ejection fraction is given as a percentage with the normal range being between 50 and 75%. The two types are:
Heart failure due to reduced ejection fraction (HFrEF). This type is also known as heart failure due to left ventricular systolic dysfunction or systolic heart failure. This type of heart failure occurs when the ejection fraction is less than 40%.
Heart failure with preserved ejection fraction (HFpEF). This type is also known as diastolic heart failure or heart failure with normal ejection fraction. This type of heart failure occurs when the heart muscle contracts well but the ventricle does not fill with blood well in the relaxation phase.