Mitral valve stenosis — or 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.
You may feel fine with mitral valve stenosis, or you may have minimal symptoms for decades. However, mild problems can suddenly worsen. See your doctor if you develop:
- Shortness of breath, especially with exertion or when you lie down
- Fatigue, especially during increased physical activity
- Swollen feet or legs
- Heart palpitations — sensations of a rapid, fluttering heartbeat
- Dizziness or fainting
- Heavy coughing, sometimes with blood-tinged sputum
- Chest discomfort or chest pain
- Severe headache, trouble speaking or other symptoms of stroke
Mitral valve stenosis symptoms may appear or worsen anytime your heart rate increases, such as during exercise. An episode of rapid heartbeats may accompany these symptoms. Or they may be triggered by pregnancy or other body stress, such as an infection.
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.
Symptoms of mitral valve stenosis most often appear in between the ages of 30 and 50 in developed nations, but they can occur at any age — even during childhood.
Mitral valve stenosis may also produce signs that your doctor will find during your examination. These may include:
- Heart murmur
- Fluid buildup in the lungs
- Irregular heart rhythms (arrhythmias)
When to see a doctor
Call your doctor for an immediate appointment if you develop fatigue or shortness of breath during physical activity, heart palpitations or chest pain.
If you've been diagnosed with mitral valve stenosis but haven't had symptoms, talk to your doctor about 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 ring around the mitral valve (annulus), which can occasionally cause mitral valve stenosis.
- Other causes. In rare cases, babies are born with a narrowed mitral valve (congenital defect) that causes problems over time. Surgery is usually recommended to repair congenital mitral stenosis. Other rare causes include radiation to the chest and some autoimmune diseases, such as lupus.
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 is less common today than 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:
- History of rheumatic fever
- Untreated strep infections
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:
- Pulmonary hypertension. This is a condition in which there's increased pressure in the arteries that carry blood from your heart to your lungs (pulmonary arteries), causing your heart to work harder.
- Heart failure. A narrowed mitral valve interferes with blood flow. This can cause pressure to build in your lungs, leading to fluid accumulation. The fluid buildup strains the right side of the heart, leading to right heart failure. With severe narrowing of the mitral valve, over time, the heart's ability to pump blood may be reduced.
- 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 irregularity 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.
- Lung congestion (pulmonary edema). Blood and fluid can back up into your lungs, leading to shortness of breath and, sometimes, coughing up of blood-tinged sputum.
Your family doctor may be the first to suspect mitral valve stenosis. After your initial appointment, your doctor may refer you to a doctor who specializes in heart conditions (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 cardiac 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.
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 also will listen to your lungs to check 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. For testing, you may be referred to a cardiologist.
Common tests to diagnose mitral valve stenosis include:
- Transthoracic echocardiogram. Sound waves directed at your heart from a wand-like device (transducer) held on your chest produce video images of your heart in motion. This test is used to confirm the diagnosis of mitral stenosis.
- Electrocardiogram (ECG). Wires (electrodes) attached to pads on your skin measure electrical impulses 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 exertion.
- Chest X-ray. This enables your doctor to determine whether any chamber of the heart is enlarged and the condition of your lungs.
- Transesophageal echocardiogram. A small transducer attached to the end of a tube inserted down your esophagus allows a closer look at the mitral valve than a regular echocardiogram does.
- Cardiac catheterization. This invasive technique isn't performed routinely for mitral stenosis, but it might be used when more information is needed to assess your condition. It involves threading a thin tube (catheter) through a blood vessel in your arm or groin to an artery in your heart and injecting dye through the catheter to make the artery visible on an X-ray. This provides a detailed picture of your heart.
Cardiac tests such as these help your doctor distinguish mitral valve stenosis from other heart conditions, including other mitral valve conditions. These tests also help reveal the cause of your mitral valve stenosis and whether the valve can be repaired.
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.
No medications can correct a mitral valve defect. However, certain drugs can reduce symptoms by easing your heart's workload and regulating its rhythm.
Your doctor might prescribe:
- Diuretics to reduce fluid accumulation in your lungs or elsewhere.
- Blood thinners (anticoagulants) to help prevent blood clots. A daily aspirin may be included.
- Beta blockers or calcium channel blockers to slow your heart rate and allow your heart to fill more effectively.
- Anti-arrhythmics to treat atrial fibrillation or other rhythm disturbances associated with mitral valve stenosis.
- Antibiotics to prevent a recurrence of rheumatic fever if that's what caused your mitral stenosis.
You may need valve repair or replacement to treat mitral valve stenosis. Surgical and nonsurgical options are available.
Repair with balloon valvuloplasty
This nonsurgical procedure uses a soft, thin tube (catheter) tipped with a balloon. A doctor guides the catheter through a blood vessel in your arm or groin 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.
For some people, balloon valvuloplasty relieves the signs and symptoms of mitral valve stenosis as well as surgery. If your condition worsens over time, you may need the procedure repeated.
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.
Mitral valve surgery
Surgical options include:
- Commissurotomy. If balloon valvuloplasty isn't an option, a cardiac surgeon might perform open-heart surgery to remove calcium deposits and other scar tissue to clear the valve passageway. Open 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 redevelops.
Mitral valve replacement. Your surgeon removes the narrowed valve and replaces it with a mechanical or tissue valve. Mechanical valves, made from metal, are durable but carry the risk of blood clots forming. If you receive a mechanical mitral valve, you'll need to take an anticoagulant medication, such as warfarin (Coumadin), for life to prevent blood clots.
Tissue valves — which may come from a pig, cow or human deceased donor — often eventually need to be replaced. Your doctor can discuss the risks and benefits of each type of heart valve with you.
To improve your quality of life if you have mitral valve stenosis, your doctor may recommend that you:
- Take care of your teeth. Brush and floss and see your dentist regularly.
- Limit salt. Salt in food and drinks may increase pressure on your heart. Don't add salt to food, and avoid high-sodium foods. Read food labels and ask for low-salt dishes when eating out.
- Maintain a healthy weight. Keep your weight within a range recommended by your doctor.
- Cut back on caffeine. Caffeine can worsen irregular heartbeats (arrhythmias). Ask your doctor about drinking beverages with caffeine, such as coffee or soft drinks.
- Seek prompt medical attention. If you notice frequent palpitations or feel your heart racing, seek medical help. Fast heart rhythms that aren't treated can lead to rapid deterioration in people with mitral valve stenosis.
- Cut back on alcohol. Heavy alcohol use can cause arrhythmias and make symptoms worse. Ask your doctor about the effects of alcohol on your heart.
- 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 for cardiovascular fitness. Ask your doctor for guidance before starting to exercise, especially if you're considering competitive sports.
- See your doctor regularly. Establish a regular appointment schedule with your cardiologist or primary care provider.
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 your heart pumps. Throughout your pregnancy and after delivery, your cardiologist and obstetrician should monitor you.
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.