Mitral valve regurgitation

DEFINITION

Mitral valve regurgitation — also called mitral regurgitation, mitral insufficiency or mitral incompetence — is a condition in which your heart’s mitral valve doesn’t close tightly, allowing blood to flow backward in your heart. As a result, blood can’t move through your heart or to the rest of your body as efficiently, making you feel tired or out of breath.

Treatment of mitral valve regurgitation depends on how severe your condition is, whether it’s getting worse and whether you have symptoms. For mild leakage, treatment may not be necessary.

You may need heart surgery to repair or replace the valve for severe leakage or regurgitation. Left untreated, severe mitral valve regurgitation can cause heart failure or heart rhythm problems (arrhythmias). Even people without symptoms should be seen and evaluated by a cardiologist and surgeon specializing in mitral valve disease to determine whether early intervention may be beneficial.

CAUSES

How the heart works

The heart, the center of your circulatory system, consists of four chambers. The two upper chambers (atria) receive blood. The two lower chambers (ventricles) pump blood.

Four heart valves open and close to let blood flow in only one direction through your heart. The mitral valve — which lies between the two chambers on the left side of your heart — is comprised of two flaps of tissue called leaflets.

The mitral valve opens when blood flows from the left atrium to the left ventricle. Then the flaps close to prevent the blood that has just passed into the left ventricle from flowing backward.

In mitral valve regurgitation, the mitral valve doesn’t close tightly. With each heartbeat, some blood from the left ventricle flows backward into the left atrium instead of moving forward into the aorta. This essentially means that the heart pulls blood backward.

Mitral valve regurgitation causes

Mitral valve regurgitation is classified as primary and secondary. Primary mitral valve regurgitation is caused by an abnormality in the mitral valve. Secondary mitral valve regurgitation is caused by an abnormality in the left ventricle of the heart.

Possible causes of mitral valve regurgitation include:

• Mitral valve prolapse. In this condition, the leaflets and tendon-like cords supporting the mitral valve weaken and stretch so that with each contraction of the left ventricle, the valve leaflets bulge (prolapse) into the left atrium. This common heart defect can prevent the mitral valve from closing tightly and lead to regurgitation.
• Damaged tissue cords. Over time, the tissue cords that anchor the flaps of the mitral valve to the heart wall may stretch or tear, especially in people with mitral valve prolapse. A tear can cause substantial leakage through the mitral valve relatively suddenly and may require repair by heart surgery. Trauma to the chest also can rupture the cords.
• Rheumatic fever. Rheumatic fever — a complication of untreated strep throat and once a common childhood illness in the United States — can damage the mitral valve, leading to mitral valve regurgitation early or later in life. Rheumatic fever is rare in the United States, but still common in developing countries.
• Endocarditis. The mitral valve may be damaged by an infection of the lining of the heart (endocarditis) that can involve heart valves.
• Heart attack. A heart attack can damage the area of the heart muscle that supports the mitral valve, affecting the function of the valve. If the damage is extensive enough, a heart attack can cause sudden and severe mitral valve regurgitation.
• Abnormality of the heart muscle (cardiomyopathy). Over time, certain conditions, such as high blood pressure, can cause your heart to work harder, gradually enlarging your heart’s left ventricle. This can stretch the tissue around your mitral valve, which can lead to leakage.
• Trauma. Experiencing trauma, such as in a car accident, can lead to mitral valve regurgitation.
• Congenital heart defects. Some babies are born with defects in their hearts, including damaged heart valves.
• Certain drugs. Prolonged use of certain medications can cause mitral valve regurgitation, such as those containing ergotamine (Cafergot, Migergot) that are used to treat migraines and other conditions.
• Radiation therapy. In rare cases, radiation therapy for cancer that is focused on the chest area can lead to mitral valve regurgitation.

SYMPTOMS

Many people with severe mitral valve regurgitation may not have symptoms, yet may still benefit from early mitral valve repair. Signs and symptoms of mitral valve regurgitation, which depend on its severity and how quickly the condition develops, can include:

• Blood flowing turbulently through your heart (heart murmur)
• Shortness of breath (dyspnea), especially with exertion or when you lie down
• Fatigue, especially during times of increased activity
• Heart palpitations — sensations of a rapid, fluttering heartbeat
• Swollen feet or ankles

Mitral valve regurgitation is often mild and progresses slowly. You may have no symptoms for decades and be unaware that you have this condition, and it might not progress.

Your doctor might first suspect you have mitral valve regurgitation upon detecting a heart murmur. Sometimes, however, the problem develops quickly, and you may experience a sudden onset of severe signs and symptoms.

When to see a doctor

If you have a murmur, you should see your doctor, who may recommend that you visit a cardiologist and get an echocardiogram. If you develop symptoms that suggest mitral valve regurgitation or another problem with your heart, see your doctor right away. Sometimes the first indications are actually those of mitral valve regurgitation’s complications, including heart failure, a condition in which your heart can’t pump enough blood to meet your body’s needs.