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Mitral Valve Stenosis - Overview


What is mitral valve stenosis?

Mitral valve stenosis is a heart problem in which the mitral valve doesn't open as wide as it should. The valve becomes stiff or scarred, or the valve flaps become partially joined together.

See a picture of mitral valve stenosis camera.gif.

Mitral valve stenosis can lead to heart failure; a stroke; an infection in the heart (endocarditis); or a fast, slow, or uneven heartbeat (arrhythmia). Fortunately, mitral valve stenosis can be treated.

Mitral valve stenosis is not common in developed countries such as the United States, Canada, and western Europe.

How does the mitral valve work?

Your heart has four chambers and four valves. The valves have flaps, or leaflets. The flaps open and close to keep blood flowing in the proper direction through your heart.

The mitral valve connects the heart's upper left chamber (left atrium) to the lower left chamber (left ventricle). When the heart pumps, blood forces the flaps open, and blood flows from the left atrium to the left ventricle. Between heartbeats, the flaps close tightly so that blood does not leak backward through the valve.

With mitral valve stenosis, not as much blood can flow into the left ventricle. More blood stays in the left atrium, and blood may back up into the lungs.

See a picture of the heart and its chambers, valves, and blood flow camera.gif.

See a picture of a normal mitral valve camera.gif.

What causes mitral valve stenosis?

Nearly all cases of mitral valve stenosis are caused by rheumatic fever. This fever results from an untreated strep infection, most often strep throat. But many people who have mitral valve stenosis don't realize that they had rheumatic fever.

What are the symptoms?

Symptoms usually don't develop until 10 to 20 years after stenosis starts, and they may take as long as 40 years to develop.

When symptoms first appear, they usually are mild. You may only have a few symptoms, even if your mitral valve is very narrow. An early symptom is shortness of breath when you are active. This shortness of breath may seem normal to you.

Symptoms later in the disease may include:

  • Shortness of breath even when you have not been very active or when you are resting.
  • Feeling very tired or weak.
  • Pounding of the heart (palpitations).

Call your doctor if your symptoms get worse or you have new symptoms.

How is mitral valve stenosis diagnosed?

Mitral valve stenosis may not be diagnosed until you've had the disease for some time. If you don't have symptoms, the first clue might be a heart murmur your doctor hears during a routine checkup.

Your doctor will ask you questions about your past health and do a physical exam. If your doctor thinks you might have the disease, he or she may do more tests. These may include:

  • An echocardiogram. This ultrasound test lets your doctor see a picture of your heart, including the mitral valve.
  • An electrocardiogram (EKG or ECG). This test can check for problems with your heart rhythm.
  • A chest X-ray. This shows your heart and lungs and can help your doctor find the cause of symptoms such as shortness of breath.

These tests also help your doctor find what caused the stenosis and how severe it is.

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