Content provided by the Faculty of the Harvard Medical School

Ask the doctor: Is an enlarged heart bad for you?

Ask the doctor

Is an enlarged heart bad for you?

Q. Is it bad to have an enlarged heart? If so, what are some of the symptoms?

A. Whether an enlarged heart is bad depends on why a person has one.

Marathon runners and other athletes who routinely pump a lot of blood for long periods of time often develop enlarged hearts. In them, the condition isn’t harmful. Most of the time, though, an enlarged heart is not a positive sign.

One common cause for an enlarged heart is weakening of the ventricles, the muscular lower chambers of the heart that pump blood to the body and the lungs. A heart attack can weaken a ventricle, as can an infection or a poison that directly affects the heart muscle. One such poison is alcohol in excess. Asking your heart to work too hard can also cause it to enlarge. A leaky heart valve, for example, forces the heart to work extra hard to supply the body with the oxygen-rich blood it needs. Pumping blood against high pressure in the arteries strains the heart, too. Inherited conditions such as hypertrophic cardiomyopathy also cause a large or overly muscular heart.

Abnormal enlargement of the heart often causes shortness of breath due to the buildup of pressure and fluid in the lungs. It causes some people to cough, particularly when they lie flat at night. Swelling of the legs is another sign of an enlarged heart (though this can have other causes as well).

If you have been told you have an enlarged heart and you have any of these symptoms, fainting spells, or marked fatigue, make an appointment to see your doctor sooner rather than later.

— Thomas H. Lee, M.D. Editor-in-Chief, Harvard Heart Letter

Last updated:	August 21, 2006