With each heartbeat, the heart contracts (or squeezes) and relaxes. Every contraction pushes blood out of the two pumping chambers (ventricles). When when heart relaxes, the ventricles refill with blood. 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 if you have heart failure or other types of heart disease.
A normal heart pumps just over half the heart's volume of blood with each beat – a normal EF is 50 to 75 percent.
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