DEAR DOCTOR K >> My doctor says I have a leaky mitral valve. What does this mean? And does it need to be treated if it's not causing symptoms?

DEAR READER >> The four valves of your heart work like one-way swinging doors: They open and close in a perfectly timed sequence to keep blood flowing through your heart in the right direction.

Your heart is a pump with four chambers. Oxygen-poor blood enters one chamber. Then it flows into a second chamber, from which it gets pumped to the lungs. There it gets oxygen and returns to a third chamber, and finally into a fourth chamber. From there, the oxygen-rich blood is pumped around the body.

The "leaflets" of a person's valves (flaps of tissue that make up the valves) and nearby structures don't always function as they should. Perhaps because of the higher pressures in the heart's left side, the valves there are particularly vulnerable to problems. That includes the mitral valve, which separates the left upper and lower chambers of the heart.

If the mitral valve is misshapen or misaligned, it can't close tightly between heartbeats. As a result, some blood spurts backward with each contraction. This backflow is known as mitral valve regurgitation — or a "leaky" mitral valve. It often creates a whooshing sound (called a heart murmur) when heard through a stethoscope.


Your doctor may suspect you have mitral regurgitation if you have a heart murmur or symptoms of the condition such as feeling breathless or very tired. You'll get an echocardiogram, a test that uses sound waves to create pictures of the heart in action. It measures blood flow back and forth through the mitral valve as well as the diameter of the heart at the end of a heartbeat.

In most people with a leaky mitral valve, the leak is too small to cause problems. However, severe mitral regurgitation can strain the heart and lead to atrial fibrillation or heart failure. Atrial fibrillation is a rapid or irregular heartbeat. Heart failure is a condition in which the heart can't effectively pump blood throughout the body. Medication may ease the symptoms of a leaky valve, but it can't correct the fact that the valve leaks.

When mitral regurgitation causes symptoms, surgery is definitely in order. But even if you don't have symptoms, your heart's left side may slowly enlarge and lose its ability to pump effectively. That's why many heart surgeons say it's better to fix the valve earlier rather than later.

If your leaky valve needs treatment — which it very well may not — there are effective options for you to consider.

Dr. Komaroff is a physician and professor at Harvard Medical School.