Understanding Ejection Fraction

Q: My doctor talks about "ejection fraction," but I don't understand what it means. Should it be 100 percent?

A: The ejection fraction is a measure of the heart’s ability to pump blood to all areas of the body. It refers to the percentage of blood that the heart sends out to the body with each heartbeat. A normal ejection fraction is 55–70 percent.
           
The ejection fraction may be lower when the heart muscle is damaged by heart muscle disease or a heart attack.

Jennifer H. Mieres, M.D., is director of nuclear cardiology and associate professor of clinical medicine at New York University. She’s also a spokeswoman for the American Heart Association.