Mitral stenosis is a heart valve disorder that involves the mitral valve. This valve separates the upper and lower chambers on the left side of the heart. Stenosis refers to a condition in which the valve does not open fully, restricting blood flow.

Mitral stenosis prevents the valve from opening properly. This prevents proper blood flow between the left atrium (upper chamber of the heart) and left ventricle (lower chamber of the heart). As the valve area becomes smaller, less blood flows to the body. The upper heart chamber swells as pressure builds up. Blood may flow back into the lungs. Fluid then collects in the lung tissue ( pulmonary edema), making it hard to breathe. See also: heart failure.

In adults, mitral stenosis occurs most often in those who've had rheumatic fever (a condition that may develop after strep throat or scarlet fever). The valve problems develop 5 - 10 years after the rheumatic fever. Rheumatic fever is becoming rare in the United States, so mitral stenosis is also less common.

Only rarely do other factors cause mitral stenosis in adults. These include calcium deposits forming around the mitral valve, radiation treatment to the chest, and some medications.

Children may be born with mitral stenosis (congenital) or other birth defects involving the heart that cause mitral stenosis. Often, there are other heart defects present, along with the mitral stenosis.

Mitral stenosis may run in families.

In adults there may be no symptoms at all. Symptoms may, however, appear or get worse with exercise or any activity that raises the heart rate. In adults, symptoms usually develop between the ages of 20 and 50.

Symptoms may begin with an episode of atrial fibrillation or may be triggered by pregnancy or other stress on the body such as infection in the heart or lungs, or other heart disorders.

Symptoms may include:

• Chest discomfort (rare)
  • Increases with activity, decreases with rest
  • Radiates to the arm, neck, jaw, or other areas
  • Tight, crushing, pressure, squeezing, constricting
• Cough, possibly bloody (hemoptysis)
• Difficulty breathing during or after exercise or when lying flat; may wake up with difficulty breathing
• Fatigue, becoming tired easily
• Frequent respiratory infections such as bronchitis
• Sensation of feeling the heart beat (palpitations)
• Swelling of feet or ankles

In infants and children, symptoms may be present from birth (congenital), and almost always develop within the first 2 years of life. Symptoms include:

• Bluish discoloration of the skin or mucous membranes (cyanosis)
• Poor growth
• Shortness of breath

The health care provider will listen to the heart and lungs with a stethoscope. A distinctive murmur, snap, or other abnormal heart sound may be heard. The typical murmur is a rumbling sound that is heard over the heart during the resting phase of the heartbeat. The sound gets louder just before the heart begins to contract.

The exam may also reveal an irregular heartbeat or lung congestion. Blood pressure is usually normal.

Narrowing or obstruction of the valve or swelling of the upper heart chambers may show on:

• Cardiac catheterization
• Chest x-ray
• Doppler ultrasound
• Echocardiogram
• ECG (electrocardiogram)
• MRI of the heart
• Transesophageal echocardiogram (TEE)

Treatment depends on the symptoms and condition of the heart and lungs. People with mild symptoms or none at all may not need treatment. Hospitalization may be required for diagnosis and for treatment of severe symptoms.

There are a number of different treatment options.

Medications are used to treat symptoms of heart failure or abnormal heart rhythms (most commonly atrial fibrillation). These include diuretics (water pills), nitrates, beta-blockers, and others. High blood pressure should also be treated.

Anticoagulants (blood thinners) are used to prevent blood clots from forming and traveling to other parts of the body.

Some patients may need heart surgery to repair or replace the valve. Replacement valves can be made from different materials, some of which may last for decades and others which can wear out and require replacement.

Percutaneous mitral balloon valvotomy (also called valvuloplasty) may be considered instead of surgery. During this procedure, a catheter (tube) is inserted into a vein, usually in the leg, and up into the heart. A balloon on the tip of the catheter is inflated, widening the mitral valve and improving blood flow. This procedure is less likely to work in patients with severely damaged mitral valves.

Children often require surgery to either repair or replace the mitral valve.

People with mitral stenosis should inform their health care provider of their condition before any procedures or surgeries. Dental work, including cleaning, and any invasive procedure, such as colonoscopy, can introduce bacteria into the bloodstream. These bacteria can infect a damaged heart valve. Although patients with valve problems are no longer automatically given antibiotics before any dental or other procedure, antibiotics may still be recommended in certain cases to help decrease the risk of valve infection and complications.

See also:

• Heart failure
• Mitral valve surgery - minimally invasive
• Mitral valve surgery - open

The outcome varies. The disorder may be mild, without symptoms, or may be more severe and eventually disabling. Complications may be severe or life threatening. Mitral stenosis is usually controllable with treatment and improved with valvuloplasty or surgery.

• Atrial fibrillation and atrial flutter
• Blood clots to the brain (stroke), intestines, kidneys, or other areas
• Heart failure
• Pulmonary edema
• Pulmonary hypertension

Call your health care provider if you have symptoms of mitral stenosis.

Call your health care provider if you have mitral stenosis and symptoms do not improve with treatment, or if new symptoms appear.

Follow the health care provider's recommended treatment for conditions that may cause valve disease. Treat strep infections promptly to prevent rheumatic fever. Tell your health care provider if you have a family history of congenital heart diseases.

Mitral stenosis itself often cannot be prevented, but complications can be prevented. Inform your health care provider of your heart valve disease before you receive any medical treatment.

Otto CM, Bonow RO. Valvular heart disease. In: Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007: chap 62.

Karchmer AW. Infective Endocarditis. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 8th ed. St. Louis, Mo: WB Saunders; 2007: chap. 63.

Nishimura RA, Carabello BA, Faxon DP, et al. ACC/AHA 2008 Guideline update on valvular heart disease: Focused update on infective endocarditis: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008;52(8):676-85.

Valvular Heart Disease. In: Park MK, ed. Pediatric Cardiology for Practitioners. 5th ed. Mosby Elsevier, 2008. Chap: 21.