Mitral valve prolapse

Alternative names
Barlow’s syndrome; Floppy mitral valve; Myxomatous mitral valve; Billowing mitral valve; Systolic click-murmur syndrome; Prolapsing mitral leaflet syndrome

Mitral valve prolapse is a disorder in which the heart’s mitral valve - which separates the left upper chamber (atrium) from the left lower chamber (ventricle) - billows out and does not close properly.

Causes, incidence, and risk factors

Mitral valve prolapse can be caused by a variety of mechanisms. In most cases, it is harmless and does not cause symptoms or need to be treated. In a small number of cases, it can cause severe mitral regurgitation (leakage of blood back through the valve) and needs to be treated with surgery.

Some forms of mitral valve prolapse seem to be hereditary. Mitral valve prolapse has been associated with Marfan’s syndrome (a disorder present from birth), Graves’ disease, and other disorders.

Many people with mitral valve prolapse are thin women who may have minor chest wall deformities, scoliosis, or other disorders. There may also be an atrial septal defect (a hole in the wall that separates the left and right upper heart chambers) high in the wall of the heart (called an ostium secundum defect).


  • sensation of feeling the heart beat (palpitations)  
  • chest pain (unrelated to coronary artery disease or a heart attack)  
  • difficulty breathing after exertion  
  • fatigue  
  • cough  
  • shortness of breath when lying flat (orthopnea)

Note: In some cases, there may be no symptoms or there may be a gradual onset of symptoms.

Signs and tests

The doctor may feel a thrill (vibration) over the heart. Using a stethoscope, the doctor may hear a distinctive murmur or other abnormal sounds. (The murmur is described as a mid-systolic click and is sometimes followed by a late systolic murmur. This means a click sound is heard midway in the “beating” part of the heartbeat cycle, followed by a murmur near the end of this time.) The murmur is worse when standing. Blood pressure is usually normal.

Mitral valve prolapse and associated regurgitation may show on:

  • Echocardiogram (an ultrasound examination of the heart)  
  • Color-flow Doppler examination  
  • Cardiac catheterization  
  • Chest X-rays (will show fluid in the lungs or an enlarged left atrium if severe mitral regurgitation is present)  
  • ECG (may show arrhythmias such as atrial fibrillation)  
  • Other tests, including chest MRI, radionuclide scans, or CT scan of the chest


In most cases there are no or few symptoms and treatment is not necessary. There are no restrictions on activity or diet.

Hospitalization may be required for diagnosis or treatment of severe symptoms. Surgical repair or valve replacement may be required if severe mitral regurgitation develops, or if symptoms worsen.

Antibiotics are prescribed if bacterial infection is present or if dental work is planned. Anti-arrhythmics (drugs which regulate the heart rhythm) may be needed to control irregular heart rhythms. Vasodilators (drugs that dilate blood vessels) reduce the workload of the heart. Digitalis may be used to strengthen the heartbeat, and diuretics (water pills) may be used to remove excess fluid in the lungs.

Propranolol may be given for palpitations or chest pain. Anticoagulants (blood thinners) may be used to prevent clot formation if atrial fibrillation is present; atrial fibrillation increases the chances of clot formation).

Expectations (prognosis)

The outcome varies depending on underlying conditions. Mitral valve prolapse is usually benign and without symptoms. When symptomatic, it is controllable with medications and may be improved with surgery. Some arrhythmias associated with this condition can be fatal, however.


  • endocarditis - valve infection  
  • severe mitral regurgitation  
  • stroke  
  • clots to other areas  
  • arrhythmias, including atrial fibrillation

Calling your health care provider

Call your health care provider if symptoms suggest mitral valve prolapse.

Call your health care provider if signs of infection occur during treatment: fever, chills, muscle aches, headache, or malaise (general ill feeling).

This condition itself may not be preventable, but some complications are. Discuss any history of heart valve disease or congenital heart disease before any treatment by the health care provider or dentist.

Any dental work, including cleaning, and any invasive procedure can introduce bacteria into the bloodstream. This bacteria can infect a damaged mitral valve, causing endocarditis.

Giving antibiotics to prevent infection (rather than waiting for infection to develop) is recommended for individuals with mitral valve prolapse when a significant regurgitation is documented. Other physicians recommend antibiotics when moderate to severe mitral valve prolapse has been confirmed and a “click” is present at auscultation.

Johns Hopkins patient information

Last revised: December 6, 2012
by Dave R. Roger, M.D.

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