Mitral Valve Prolapse


What Is It?

Mitral valve prolapse, also known as Barlow’s syndrome or systolic click-murmur syndrome, is a malfunction of the heart’s mitral valve, the physical doorway between the heart’s left atrium and left ventricle. Normally, the mitral valve closes when the ventricle’s muscles contract, preventing a blood from flowing back into the left atrium when the heart pumps blood to the rest of the body. In mitral valve prolapse, however, a slight deformity of the mitral valve prevents the valve from closing normally. This appears as an abnormal floppiness or “prolapse” of the valve. The result is that small amounts of blood leak back into the left atrium, with very little effect on the heart’s overall ability to pump blood.

In some people, the leakage progresses to mitral regurgitation, a significant backflow of blood into the left atrium. People with severe mitral regurgitation can develop symptoms such as shortness of breath, fatigue and leg swelling. Rarely, heart surgery is needed to repair these damaged valves.

In most people with mitral valve prolapse, the cause is unknown. However, in a small number of patients, mitral valve prolapse may be related to another medical condition, such as an inherited abnormality in the way the body produces collagen (connective tissue), or rheumatic heart disease (a rare complication of strep throat).

Health experts estimate that mitral valve prolapse currently affects up to 5 percent of people in the United States. For unknown reasons, the condition is most common in women between 14 to 30. Although the condition sometimes affects several members of the same family, no specific genetic (inherited) basis has been identified for the problem.


Most people with mitral valve prolapse do not have any symptoms, and the condition is discovered only when a doctor hears a specific type of heart murmur during a routine physical examination. Some people may develop palpitations, a racing pulse, fainting or a feeling of lightheadedness. There also may be prolonged chest pain, usually located under the breastbone, which, unlike angina (the chest pain of coronary artery disease), is not necessarily related to stress or exercise. In the people with mitral regurgitation (about 15 percent of patients with mitral valve prolapse for 15 years), there may be symptoms of congestive heart failure (fatigue, shortness of breath, leg swelling).


Your doctor will review your medical history, including any history of heart disease, and will ask questions about symptoms such as anxiety, palpitations, light-headedness, fainting and chest pain. He or she also will ask about your family’s history of heart disease.

You and your doctor may not suspect that you have mitral valve prolapse until your doctor hears a sound called a systolic click with the stethoscope during the cardiac portion of a routine physical examination. The systolic click is an abnormal heart sound related to the malfunction of the mitral valve in mitral valve prolapse. In some patients, an additional heart murmur (an abnormal heart sound produced by turbulent blood flow) also can be heard.

Once your doctor suspects that you have mitral valve prolapse, the diagnosis can be confirmed by showing abnormal mitral valve movement during two-dimensional echocardiography. This is a painless test that uses sound waves to map out your heart structure. Further tests may be needed if you have dizziness, palpitations, a history of fainting or chest pain, symptoms which suggest that you might have an irregular heartbeat (cardiac arrhythmia).

Expected Duration

Mitral valve prolapse is a lifelong condition. However, most people with the condition do not have any symptoms.


There is no way to prevent mitral valve prolapse.


If you have mitral valve prolapse, but do not have any symptoms, history of cardiac arrhythmias or signs of mitral regurgitation, then you probably will not need treatment. If your mitral valve is leaking enough to cause a heart murmur, you may be given antibiotics to prevent an infection of the heart valve called endocarditis. If you have chest pain or a cardiac arrhythmia, you may be treated with medications such as beta-blockers. If mitral valve prolapse progresses to severe mitral regurgitation, the abnormal mitral valve may need to be repaired or replaced surgically.

When To Call A Professional

Call your doctor immediately if you have palpitations or an abnormal pulse, especially if these symptoms have also made you feel light-headed or faint. Also, call your doctor immediately if you have chest pain at any age.


Most patients with mitral valve prolapse never have symptoms, and the condition never progresses to a point where it significantly affects their lifestyle or life expectancy. Surgery to reconstruct or replace the mitral valve is successful in more than 90 percent of patients. Although it is possible for a patient with mitral valve prolapse to die suddenly from a fatal cardiac arrhythmia, this is very, very rare.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.