No one's heart pumps at 100 percent. In fact, most hearts pump only a little more than half their volume with each beat. That proportion is called your ejection fraction (EF)- and it can mean the difference between normal heart function and heart failure.

Weakened Hearts

A normal ejection fraction, or EF, is 55 percent, but it can range from 50 to 80 percent. In people with conditions that weaken the heart, though, EF can drop below normal. A low EF can be caused by:

Damage to the heart from a heart attack or coronary artery disease

Heart valve problems

Diseases such as dilated cardiomyopathy, which leads to an enlarged heart

Drugs used to treat cancer

A low EF indicates heart failure - the heart's inability to pump enough blood to keep up with the body's needs. It can also increase your risk for abnormal heart rhythms, which can lead to sudden cardiac arrest - the abrupt stopping of heart function.

Part of the Puzzle

You may benefit from having your EF checked if you have a history of cardiomyopathy or you are taking drugs to treat cancer. In fact, an EF reading is part of several diagnostic heart tests.
Several medicines can raise a low EF, including ACE (angiotensin-converting enzyme) inhibitors and beta-blockers. Healthy lifestyle choices are also important to keep your EF in a healthy range. Eat a healthy diet low in salt, get as much exercise as your doctor recommends, and don't smoke. If the cause is coronary artery disease, angioplasty or bypass surgery may be necessary.