Mitral valve stenosis — sometimes called mitral stenosis — is a narrowing of the heart's mitral valve. This abnormal valve doesn't open properly, blocking blood flow into the main pumping chamber of your heart (left ventricle). Mitral valve stenosis can make you tired and short of breath, among other problems.

The main cause of mitral valve stenosis is an infection called rheumatic fever, which is related to strep infections. Rheumatic fever — now rare in the United States, but still common in developing countries — can scar the mitral valve. Left untreated, mitral valve stenosis can lead to serious heart complications.

In mitral valve stenosis, pressure that builds up in the heart is then sent back to the lungs, resulting in fluid buildup (congestion) and shortness of breath.

The condition usually progresses slowly over time. You may feel fine with mitral valve stenosis, or you may have mild symptoms for decades. Symptoms of mitral valve stenosis typically appear between the ages of 15 and 40, but they can occur at any age — even during childhood.

Signs and symptoms of mitral valve stenosis include:

• Shortness of breath, especially with activity or when you lie down
• Fatigue, especially during increased activity
• Swollen feet or legs
• Sensations of a rapid, fluttering heartbeat (palpitations)
• Chest discomfort or chest pain
• Coughing up blood
• Dizziness or fainting
• Heart murmur
• Fluid buildup in the lungs
• Irregular heart rhythms (arrhythmias)

Mitral valve stenosis symptoms may appear or worsen anytime your heart rate increases, such as during exercise. Or they may be triggered by pregnancy or other things that cause stress on the body, such as an infection.

When to see a doctor

Call your doctor for an immediate appointment if you have fatigue or shortness of breath during physical activity, heart palpitations or chest pain.

If you have been diagnosed with mitral valve stenosis but haven't had symptoms, ask your doctor about how often you should have follow-up evaluations.

Causes of mitral valve stenosis include:

• Rheumatic fever. A complication of strep throat, rheumatic fever can damage the mitral valve. Rheumatic fever is the most common cause of mitral valve stenosis. It can damage the mitral valve by causing the flaps to thicken or fuse. Signs and symptoms of mitral valve stenosis might not show up for years.
• Calcium deposits. As you age, calcium deposits can build up around the mitral valve (annulus), which can occasionally cause mitral valve stenosis.
• Radiation therapy. Treatment for certain types of cancer that requires radiation to your chest area can sometimes cause the mitral valve to thicken and harden.
• Other causes. In rare cases, babies are born with a narrowed mitral valve (congenital defect) that causes problems over time. Some autoimmune diseases, such as lupus, also may rarely cause mitral valve stenosis.

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 — comprises 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. A defective heart valve fails to either open or close fully.

Mitral valve stenosis isn't as common as it once was because the most common cause, rheumatic fever, is rare in the United States. However, rheumatic fever remains a problem in developing nations.

Risk factors for mitral valve stenosis include untreated strep infections and a history of rheumatic fever.

Older adults are at increased risk of mitral valve stenosis. As you age, calcium deposits can build up around the mitral valve, which may lead to mitral valve stenosis.

Rarely, people who receive radiation therapy to the chest area for certain types of cancer may develop mitral valve stenosis.

Like other heart valve problems, mitral valve stenosis can strain your heart and decrease blood flow. Untreated, mitral valve stenosis can lead to complications such as:

• High blood pressure in the lung arteries (pulmonary hypertension). Increased pressure in the arteries that carry blood from your heart to your lungs (pulmonary arteries) causes your heart to work harder.
• Heart failure. A narrowed mitral valve interferes with blood flow. As a result, pressure may increase in your lungs, leading to fluid buildup. The fluid buildup strains the right side of the heart, leading to right heart failure.
• Fluid in the lungs (pulmonary edema). In this condition, blood and fluid back up into your lungs. Pulmonary edema can cause shortness of breath and may cause you to cough up blood-tinged mucus.
• Heart enlargement. The pressure buildup of mitral valve stenosis results in enlargement of your heart's upper left chamber (atrium).
• Atrial fibrillation. The stretching and enlargement of your heart's left atrium may lead to this heart rhythm problem in which the upper chambers of your heart beat chaotically and too quickly.
• Blood clots. Untreated atrial fibrillation can cause blood clots to form in the upper left chamber of your heart. Blood clots from your heart can break loose and travel to other parts of your body, causing serious problems, such as a stroke if a clot blocks a blood vessel in your brain.

The best way to prevent mitral valve stenosis is to prevent its most common cause, rheumatic fever. You can do this by making sure you and your children see your doctor for sore throats. Untreated strep throat infections can develop into rheumatic fever. Fortunately, strep throat is usually easily treated with antibiotics.

Your doctor will ask about your medical history and give you a physical examination that includes listening to your heart through a stethoscope. Mitral valve stenosis causes an abnormal heart sound, called a heart murmur.

Your doctor will also listen to your lungs to check for lung congestion — a buildup of fluid in your lungs — that can occur with mitral valve stenosis.

Your doctor will then decide which tests are needed to make a diagnosis, and whether you need to be referred to a doctor who specializes in heart conditions (cardiologist).

Tests

Tests can be done to determine the cause of mitral valve stenosis and to determine if the valve can be repaired. Common tests to diagnose mitral valve stenosis include:

• Electrocardiogram (ECG). Wires (electrodes) attached to pads on your skin measure electrical signals from your heart, providing information about your heart rhythm. You might walk on a treadmill or pedal a stationary bike during an ECG to see how your heart responds to physical activity.
• Chest X-ray. A chest X-ray can help your doctor determine whether the heart is enlarged. A chest X-ray can also show the condition of your lungs.
• Transthoracic echocardiogram. Sound waves directed at your heart from a wandlike device (transducer) held on your chest produce video images of your heart in motion. This test is used to confirm the diagnosis of mitral valve stenosis.
• Transesophageal echocardiogram. A wandlike device attached to the end of a tube is inserted down your esophagus. This gives your doctor a closer look at the mitral valve than a regular echocardiogram does.
• Cardiac catheterization. This test isn't often used to diagnose mitral valve stenosis, but it may be used if other tests aren't able to diagnose the condition or determine its severity. It involves threading a thin tube (catheter) through a blood vessel, usually in your groin, to an artery in your heart. Dye flows through the catheter to make the artery appear more clearly on an X-ray.

If you have mild to moderate mitral valve stenosis with no symptoms, you might not need immediate treatment. Instead, your doctor will monitor the valve to see if your condition worsens.

Medications

No medications can correct a mitral valve defect. However, certain drugs can reduce symptoms by easing the strain on the heart and controlling your heart rhythm.

Your doctor might prescribe one or more of the following medications:

• Diuretics to reduce fluid buildup in your lungs or elsewhere.
• Blood thinners (anticoagulants) to help prevent blood clots.
• Beta blockers, calcium channel blockers or digitalis glycosides to slow your heart rate and allow your heart to fill more effectively.
• Anti-arrhythmics to treat atrial fibrillation or other irregular heart rhythms associated with mitral valve stenosis.
• Antibiotics to prevent a return of rheumatic fever if that's what caused your mitral valve stenosis.

Surgery or other procedures

You may need valve repair or replacement to treat mitral valve stenosis, which may include surgical and nonsurgical options.

• Percutaneous balloon mitral valvuloplasty. In this procedure, also called balloon valvotomy, a doctor inserts a soft, thin tube (catheter) tipped with a balloon in an artery in your arm or groin and guides it to the narrowed valve. Once in position, the balloon is inflated to widen the valve, improving blood flow. The balloon is then deflated, and the catheter with balloon is removed.

  Not everyone with mitral valve stenosis is a candidate for balloon valvuloplasty. Talk to your doctor to decide whether it's an option for you.

• Surgical commissurotomy. If balloon valvuloplasty isn't an option, a heart surgeon might perform this open-heart surgery to remove calcium deposits and other scar tissue to clear the valve passageway. Surgical commissurotomy requires that you be put on a heart-lung bypass machine during the surgery. You may need the procedure repeated if your mitral valve stenosis returns.

• Mitral valve replacement. If the mitral valve can't be repaired, surgery may be recommended to replace the damaged valve with a mechanical one or a valve made from cow, pig or human heart tissue (biological tissue valve).

  Biological tissue valves break down over time and may need to be replaced. If you have a mechanical valve, you will need to take blood thinners for life to prevent blood clots. Your doctor will discuss with you the benefits and risks of each type of valve and discuss which valve may be appropriate for you.

Lifestyle changes can help improve your heart health. If you have mitral valve stenosis, your doctor may recommend that you:

• Limit salt. Salt in food and drinks may increase pressure on your heart. Avoid high-sodium foods. Don't add salt to food. Read food labels and ask for low-salt dishes when eating out.
• Maintain a healthy weight. Ask your doctor what a healthy weight is for you.
• Cut back on alcohol and other stimulants. Heavy alcohol use, caffeine, nicotine and other stimulants can cause your heart to beat faster and worsen arrhythmias.
• Get regular exercise. How long and hard you're able to exercise may depend on the severity of your condition and the intensity of exercise. But everyone should engage in at least low-level, regular exercise. Ask your doctor for guidance before starting to exercise, especially if you're considering competitive sports.
• Quit smoking. If you smoke, talk to your doctor about programs and medications that can help you quit.
• See your doctor regularly. Have regular checkups with your cardiologist or primary care doctor. If you have frequent palpitations or feel your heart racing, get medical help. Fast heart rhythms that aren't treated can quickly get worse in people with mitral valve stenosis.

Women with mitral valve stenosis need to discuss family planning with their doctors before becoming pregnant. Pregnancy causes the heart to work harder. How a heart with mitral valve stenosis tolerates the extra work depends on the degree of stenosis and how well the heart pumps. If you're pregnant and have mitral valve stenosis, your doctors should closely monitor you.

Your family doctor may be the first to think you may have mitral valve stenosis. After your initial appointment, your doctor may refer you to a cardiologist.

Here's some information to help you prepare for your appointment.

What you can do

• Write down your symptoms and when they started.
• List your key medical information, including other health problems and prescription and over-the-counter medications and supplements you're taking.
• Take a family member or friend to the appointment, if possible. Someone who accompanies you can help remember the information you get.
• Write down the questions to ask your doctor.

Questions to ask your doctor at your initial appointment include:

• What is likely causing my symptoms?
• Are there other possible causes for these symptoms?
• What tests do I need?
• Should I see a specialist?
• Do I need to restrict anything before my cardiologist appointment?

Questions to ask if you are referred to a cardiologist include:

• What is my diagnosis?
• What treatment do you recommend?
• What are the possible side effects of the medications you're recommending?
• What will my recovery be like from the procedure you're recommending?
• How will you monitor my health over time?
• What is my risk of long-term complications from this condition?
• What restrictions do I need to follow?
• Will physical activity, including sex, increase my risk of complications?
• What diet and lifestyle changes should I make?
• I have these other health problems. How can I best manage them together?

It's important for you to understand your condition. Don't hesitate to ask other questions.

What to expect from your doctor

A doctor or cardiologist who sees you for possible mitral valve stenosis may ask:

• What are your symptoms?
• When did your symptoms begin?
• Have your symptoms worsened?
• Do you have rapid, fluttering or pounding heartbeats?
• Have you coughed up blood?
• Does exercise or physical activity worsen your symptoms?
• Are you aware of a family history of heart problems?
• Have you had rheumatic fever?
• Are you being treated or have you recently been treated for any other health conditions?
• Do you or did you smoke? How much? When did you quit?
• Do you use alcohol or caffeine? How much?
• Are you planning to become pregnant in the future?

What you can do in the meantime

While you wait for your appointment, ask family members whether close relatives have heart disease. The symptoms of mitral valve stenosis are similar to other heart conditions, including some that run in families. Knowing about your family's health history will help your doctor determine your diagnosis and treatment.

If exercise makes your symptoms worse, avoid exerting yourself physically until you've seen your doctor.