Mitral Valve Stenosis

Mitral Valve Stenosis

British Columbia Specific Information

There are several different types of heart valve disorders and many different treatments available. Treatments could include lifestyle changes, medication, or surgery. To learn more about heart valve disorders and treatments, visit the Heart and Stroke Foundation - Valve Disorders.

In some cases, a blood thinner may be prescribed as part of your treatment. Blood thinners are medicines that help prevent blood clots. If you are taking a blood thinner, always talk to your health care provider before you buy any over the counter medicines.

For more information you may also call 8-1-1 to speak to a registered nurse or pharmacist. Our nurses are available anytime, every day of the year; and our pharmacists are available every night from 5:00 p.m. to 9:00 a.m.


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.

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 Canada, the United States, 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.

See a picture of a normal mitral valve.

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?

Mitral valve stenosis is a lifelong disease, but symptoms may not happen for many years. 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 examination. 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.

How is it treated?

Treatment depends on how severe the disease and your symptoms are.

  • You'll probably need only regular checkups if you have mild or moderate stenosis.
  • You may need medicines to treat complications.
  • You may need your mitral valve repaired or replaced if you have severe symptoms, your valve is very narrow, or you are at risk for other problems, such as heart failure.

You will likely need regular echocardiograms so your doctor can check for any changes in your mitral valve and heart.

You can make lifestyle changes to keep your heart healthy. Your doctor may advise you to:

  • Quit smoking and stay away from second-hand smoke.
  • Follow a heart-healthy diet and limit sodium.
  • Be active. If your stenosis is mild, you'll probably be able to do your usual activities, get mild exercise, and play some sports. But if your stenosis is moderate or severe, you may need to avoid intense exercise. But your doctor can help you choose an activity or exercise that is safe for you.
  • Stay at a healthy weight, or lose weight if you need to.

You may need to limit sodium in your diet.


Nearly all cases of mitral valve stenosis are caused by rheumatic fever, which can follow an untreated strep throat infection. But many people who have mitral valve stenosis don't realize that they had rheumatic fever.

Other less common causes include:

  • A congenital (from birth) heart defect.
  • Infection of the valve or heart muscle (endocarditis).
  • Hardening of the valve or its parts because of aging or severe kidney disease.
  • Conditions that cause scarring of the valve (such as lupus or rheumatoid arthritis).
  • The diet medicine fen-phen. It was taken off the market in Canada and the U.S. in 1997 because of its link to heart valve disease.


Although mitral valve stenosis is a lifelong disease, symptoms may not happen for years.

Early symptoms are often mild. In the later stages, the left atrium may become damaged, causing more severe symptoms.

Symptoms of mitral valve stenosis include:

  • Shortness of breath.
  • Fatigue or weakness.
  • A pounding heart (palpitations).
  • Coughing up blood.
  • An irregular heart rhythm (because of heart failure from stenosis).

Other less common symptoms include:

  • Hoarseness and vocal cord paralysis.
  • Trouble swallowing.
  • Chest pain.
  • Skin colour changes, such as pink to purple shades on the cheeks or a dark blue colour on the body from reduced blood flow. Skin colour changes occur rarely and usually only in the end stages of the disease.

You may not have any symptoms unless you exercise, are stressed, are pregnant, or have an infection or an irregular heartbeat. Or you may have only a few symptoms, no matter how bad your stenosis is.

What Increases Your Risk

Risk factors for mitral valve stenosis are:

  • History of rheumatic fever. But since most people don't know that they had rheumatic fever, they may not know they are at risk.
  • Aging. Wear and tear of the valve over time may cause it to harden and narrow.
  • Being female. More women than men get this problem.

Diabetes and Marfan's syndrome can sometimes lead to stenosis. Any condition that scars the valves, such as endocarditis, also may cause stenosis.

When to Call a Doctor

or other emergency services immediately if you have:

Call a doctor now if you have:

  • Symptoms of heart failure, such as shortness of breath, swelling in the feet and ankles, and not being able to exercise at your usual level.
  • Mitral valve stenosis and are having symptoms of infection, such as fever with no other obvious cause.
  • Fainting episodes.
  • Excessive fatigue without another explanation.

Examinations and Tests

Mitral valve stenosis often has no symptoms in its early stages. It may not be diagnosed until you've had the disease for some time. One or more complications may lead to its diagnosis.

The first sign of mitral valve stenosis could be a heart murmur that your doctor hears during a routine checkup.

A review of your medical history and a physical examination can help your doctor find out if you have mitral valve stenosis. Your doctor also can use them to plan your treatment.

Medical history

Your doctor will ask about your lifestyle, activity level, and family health history. Your doctor will want to know about your symptoms. He or she will ask if you have ever had:

Physical examination

During the physical examination, the doctor will:

  • Listen for a certain heart murmur and other sounds that indicate a heart valve is not working right.
  • Take your blood pressure.
  • Check your pulse.
  • Look for swelling that can be a sign of too much fluid in your body.
  • Listen to your lungs to check for fluid.


An echocardiogram is used to find out if you have mitral valve stenosis and to see how bad it is. Your doctor can check your heart valve and take pictures of your heart.

In transesophageal echocardiography, a device is inserted down your throat and into your esophagus to make pictures of your heart. This may be done if your doctor wants to see a different view of your heart.

You will likely have regular echocardiograms so your doctor can keep track of any changes in your condition. Your doctor may recommend an echocardiogram every 6 to 12 months if you have severe stenosis, every 3 to 5 years if you have mild to moderate stenosis.footnote 1

A stress echocardiogram may be done to see how your heart responds to exercise.


Electrocardiogram is used to measure the electrical activity in the heart. Small pads or patches called electrodes are attached to your chest, arms, and legs. The electrodes are connected to a machine that translates the electrical activity into line tracings on paper. Your doctor looks at the tracings to check for problems.

Chest X-ray

A chest X-ray may show evidence of mitral valve stenosis. The test may show enlargement of the upper left heart chamber (left atrium) or the pulmonary arteries. Calcium deposits on the heart valves sometimes may be seen, especially if the buildup is severe.

Cardiac catheterization

Cardiac catheterization is usually done before any surgery for mitral valve stenosis to evaluate your heart, the degree of stenosis, and the health of your coronary arteries. Knowing the condition of the coronary arteries may affect later treatment decisions for stenosis.

Treatment Overview

Treatment of mitral valve stenosis is repair or replacement of the mitral valve.

Your doctor will check many things to see when treatment is right for you and what type of treatment is right for you. These things include the severity of stenosis, the shape of your mitral valve, and whether you have symptoms.

If your stenosis is mild or moderate, your doctor may only watch your condition with regular echocardiograms. Your doctor will want you to call if you notice symptoms or if you have a change in the symptoms you already have. If your stenosis is severe, your doctor may recommend valve repair or replacement.

Repair or replace the mitral valve

Repairing the valve can be done by:

  • Balloon valvotomy, a catheter procedure that stretches the valve open.
  • Commissurotomy, an open-heart surgery to remove calcium deposits and other scar tissue from the valve.

Mitral valve replacement surgery replaces the damaged valve with a new valve.

For more information, see Surgery.

Ongoing Concerns

Mitral valve stenosis can be an easy condition to overlook in its mild form. But as it gets worse, it often has serious complications. These are serious problems that need treatment.

The most common complications are:

Other complications include:

  • Fluid buildup in the lungs.
  • Spitting up blood.
  • High blood pressure in the lungs.
  • Blood clots that travel through blood vessels to the heart, brain, kidneys, intestines, arms, or legs.

For more information, see the topics Heart Failure, Atrial Fibrillation, and Endocarditis.

Living With Mitral Valve Stenosis

Long-term mitral valve stenosis can cause serious heart damage. But you can help yourself live fully by working with your doctor and having a healthy lifestyle.

Make healthy lifestyle changes

  • If you smoke, try to quit. Medicines and counselling can help you quit for good.
  • Your doctor will also recommend that you follow a heart-healthy diet and limit how much sodium you eat.
  • Be active, but you might need to avoid strenuous exercise. Ask your doctor what level of exercise is safe for you. Exercise helps keep your heart and body healthy. But when you have mitral valve stenosis, exercise can put extra strain on your heart and cause symptoms like fluid buildup in your lungs. So exercise with care and be aware of any symptoms like shortness of breath. If you don't exercise, talk to your doctor before you start.
    • If your stenosis is mild and you don't have symptoms, your doctor may encourage you to do low-level aerobic exercise.
    • If your stenosis is moderate or severe and you have symptoms, you should avoid strenuous activity. You may be able to do low-level activities to help keep your heart healthy.
    • People who have severe stenosis may need to be cautious about their level of physical activity. You may be able to do certain types of exercise that won't strain your heart.
  • If you need to lose weight, try to reach and stay at a healthy weight. For help, see the topic Weight Management.

Take care of yourself

  • See your doctor right away if yo have new symptoms or symptoms that get worse. For more information, see When to Call a Doctor.
  • See your doctor regularly, and get the tests you need to assess your heart, such as echocardiograms. For more information, see Examinations and Tests.
  • Manage other health problems, including high blood pressure, diabetes, and high cholesterol.
  • Practice good dental hygiene and have regular checkups. Good dental health is especially important, because bacteria can spread from infected teeth and gums to the heart valves.
  • Get a flu vaccine every year. Get a pneumococcal vaccine shot. If you have had one before, ask your doctor if you need another dose.
  • Talk with your doctor if you have concerns about sex and your heart. Your doctor can help you know if or when it's okay for you to have sex.


Medicines might be used to prevent or treat complications of mitral valve stenosis. Usually they are also prescribed after surgery to repair or replace the valve.

Medicines used to prevent and treat complications include:

  • Heart rate or rhythm medicines. If you have an arrhythmia, such as atrial fibrillation, you may have medicine to lower your heart rate or keep it regular.
  • Anticoagulants. If you are at risk of dangerous blood clots, you might take an anticoagulant. Things that raise your risk of blood clots include atrial fibrillation, heart valve surgery, previous blood clots, or a mechanical heart valve.
  • Heart failure medicines. If you have heart failure, you may take medicines that relieve your symptoms and slow down how quickly heart failure gets worse. These medicines help lower your blood pressure, reduce fluid buildup, and help your heart to not work so hard.
  • Antibiotics. If you have an artificial valve, you may need to take antibiotics before you have certain dental or surgical procedures. You will likely take antibiotics after surgery to repair or replace a valve. If you have had rheumatic fever, you may take antibiotics to avoid getting it again.


You may need surgery to repair or replace your mitral valve.

Deciding whether you need surgery and if so, when, depends on the severity of your disease, the possibility that it will get worse, and the risks of surgery. Your doctor will check many things including your health, the shape of your mitral valve, and whether you have symptoms.

For more information about the decision to repair or replace a mitral valve, see Mitral Valve Stenosis: Repair or Replace the Valve?


You may have one of the following procedures to repair the valve:

  • Balloon valvotomy
    : This procedure is the preferred treatment for mitral valve stenosis. A doctor uses a catheter and a tiny balloon to stretch open the narrowed valve. It is minimally invasive.

  • Repair surgery (commissurotomy)
    : This is typically an open-heart surgery using a heart-lung bypass machine. A surgeon removes calcium deposits and other scar tissue from the valve leaflets to widen the valve.


Mitral valve replacement surgery
might be done if the valve is damaged beyond repair. This surgery is typically an open-heart surgery using a heart-lung bypass machine.

If you have valve replacement surgery, a mechanical or tissue valve will be used to replace your heart valve. Before you have surgery, you and your doctor will decide which type of valve is right for you.



  1. Nishimura RA, et al. (2014). 2014 AHA/ACC guideline for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation, published online March 3, 2014. DOI: 10.1161/CIR.0000000000000031. Accessed May 1, 2014.


Current as of:
January 10, 2022

Author: Healthwise Staff
Medical Review:
Rakesh K. Pai MD, FACC - Cardiology, Electrophysiology
Brian D. O'Brien MD - Internal Medicine
Martin J. Gabica MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
John A. McPherson MD, FACC, FSCAI - Cardiology
Michael P. Pignone MD, MPH, FACP - Internal Medicine