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Mitral valve stenosis

Definition

Mitral valve stenosis or mitral stenosis is a condition in which the heart's mitral valve is narrowed (stenotic). This abnormal valve doesn't open properly, blocking blood flow coming into your left ventricle, the main pumping chamber of your heart. 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.

Symptoms

You can have mitral valve stenosis and feel fine, or you may have only minimal signs and symptoms for decades. However, mild problems can suddenly get worse. See your doctor if you develop these mitral valve stenosis symptoms:

  • Fatigue, especially during times of increased physical activity
  • Shortness of breath, especially with exertion or when you lie down
  • Swollen feet or ankles
  • Heart palpitations sensations of a rapid, fluttering heartbeat
  • Frequent respiratory infections, such as bronchitis
  • Heavy coughing, sometimes with blood-tinged sputum
  • Rarely, chest discomfort or chest pain

Mitral valve stenosis symptoms which may resemble those of other heart or heart valve conditions may appear or worsen anytime you increase your heart rate, such as during exercise. An episode of rapid heartbeats also may accompany these symptoms. Or they may also be triggered by pregnancy or other stress on your body, such as an infection.

Mitral valve stenosis symptoms usually include those of heart failure. 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 your 40s and 50s, but they can occur at any age even during infancy. Depending on the amount of narrowing, an infant or a child with mitral valve stenosis may have no symptoms, may tire easily or may have shortness of breath with vigorous physical activity.

Mitral valve stenosis may also produce a number of signs that only your doctor will be able to find. These may include:

  • Heart murmur
  • Lung congestion
  • Irregular heart rhythms (arrhythmias)
  • Pulmonary hypertension
  • Blood clots

When to see a doctor
Call your doctor for an immediate appointment if you develop symptoms such as 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 recommended follow-up.

Causes

The heart, the center of your circulatory system, consists of four chambers. The two upper chambers, the atria, receive blood. The two lower chambers, the ventricles, pump blood.

Blood flows through your heart's chambers, aided by four heart valves. These 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 consists of two triangular flaps of tissue called leaflets.

Heart valves open like a trapdoor. The mitral valve is forced open when blood flows from the left atrium into the left ventricle. When the blood has gone through the valve, the leaflets swing closed to prevent the blood that has just passed into the left ventricle from flowing backward, in the wrong direction.

A defective heart valve is one that fails to either open or close fully. When a valve becomes narrowed and blood flow through it is limited, the condition is called stenosis. Mitral valve stenosis is narrowing of the mitral valve, which obstructs blood flow into the heart's left ventricle.

Causes of mitral valve stenosis include:

  • Rheumatic fever. A complication of strep throat, rheumatic fever can damage the mitral valve, leading to mitral valve stenosis later in life. Rheumatic fever is the most common cause of mitral valve stenosis. It can damage the mitral valve in two main ways. The infection may cause the leaflets of the valve to thicken, limiting the valve's ability to open. Or the infection may cause the leaflets of the mitral valve to fuse somewhat together, preventing the valve from opening and closing properly. People with rheumatic fever may have both mitral valve stenosis and regurgitation.
  • Congenital heart defect. In rare cases, babies are born with a narrowed mitral valve and develop mitral valve stenosis early in life. Babies born with this problem usually require heart surgery to fix the valve. Others are born with a damaged mitral valve that puts them at risk of developing mitral valve stenosis when they're older. In most cases, doctors don't know why a heart valve fails to develop properly in a newborn, infant or child, so it's not something that can be prevented.
  • Other causes. Rarely, growths, blood clots or tumors can block the mitral valve, mimicking mitral valve stenosis. As you age, excessive calcium deposits can build up around the mitral valve, which sometimes causes significant mitral valve stenosis. Radiation treatment to the chest and some medications also may cause mitral valve stenosis.

Chambers and valves of the heart

Illustration showing chambers and valves of the heart
Enlarge Image
A normal heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood ...

Risk factors

Mitral valve stenosis is less common today than it was several decades ago because the most common cause, rheumatic fever, is rare in the United States. However, rheumatic fever remains a frequent problem in countries where antibiotic use isn't as common.

Risk factors for mitral valve stenosis include a history of rheumatic fever and recurrent strep infections. Radiation treatment involving the chest can result in mitral valve stenosis. Other unusual causes of mitral valve stenosis include medications, such as ergot preparations used for migraines.

Complications

Like other heart valve problems, mitral valve stenosis can weaken your heart and decrease how efficiently it pumps blood. Mitral valve stenosis reduces the amount of blood that flows forward through your heart and out to the rest of your body.

Left untreated, mitral valve stenosis can lead to complications such as:

  • Heart failure. Heart failure is a condition in which your heart can't pump enough blood to meet your body's needs. A narrowed mitral valve interferes with blood flow through your heart and from your heart out to the rest of your body. In addition, pressure builds up in your lungs, leading to fluid accumulation. Eventually, this places a strain on the right side of the heart, which leads to fluid buildup in either your ankles or abdomen or both areas (edema).
  • Heart enlargement. The pressure buildup of mitral valve stenosis results in enlargement of your heart's upper left chamber (atrium). At first this change helps your heart pump more efficiently, but eventually, it damages your heart's overall health. Additionally, pressure can build up in your lungs and cause pulmonary congestion and hypertension.
  • Atrial fibrillation. In mitral valve stenosis, the stretching and enlargement of your heart's left atrium may lead to a heart rhythm irregularity called atrial fibrillation. In atrial fibrillation, the upper chambers of your heart beat chaotically and too quickly.
  • Blood clots. Left untreated, atrial fibrillation can put you at risk of blood clots forming in the upper left chamber of your heart, where blood pools in mitral valve stenosis. Blood clots from your heart may break loose and travel to other parts of your body, causing serious problems. For example, a blood clot that travels to your brain and blocks a blood vessel there could cause a stroke.
  • Lung congestion. Another possible complication of mitral valve stenosis is pulmonary edema a condition in which blood and fluid back up into your lungs. This causes congestion of the lungs, leading to shortness of breath and, sometimes, coughing up of blood-tinged sputum.

Preparing for your appointment

Your family doctor may be the first to suspect or diagnose mitral valve stenosis. After your initial appointment, your doctor may refer you to a doctor who specializes in the diagnosis and treatment of heart conditions (cardiologist).

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

What you can do

  • Write down any symptoms you're experiencing, and for how long.
  • Make a list of your key medical information, including other recent health problems you've had and the names of any prescription and over-the-counter medications you're taking.
  • Find a family member or friend who can come with you to the appointment, if possible. Someone who accompanies you can help remember what the doctor says.
  • Write down the questions you want to be sure to ask your doctor.

Questions to ask your doctor at your initial appointment include:

  • What is likely causing my symptoms?
  • Are there any other possible causes for these symptoms?
  • What tests do I need?
  • Should I see a specialist?
  • Should I follow any restrictions in the time leading up to my appointment with a cardiologist?

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?
  • If you're recommending an invasive procedure, what will my recovery be like?
  • 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 sexual activity, 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?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.

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 you first begin experiencing symptoms?
  • Have your symptoms gotten worse over time?
  • Do your symptoms include rapid, fluttering or pounding heartbeats?
  • Have you ever coughed up blood?
  • Does exercise or physical activity make your symptoms worse?
  • Are you aware of any history of heart problems in your family?
  • Have you ever knowingly 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?
  • 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, check with your family members to find out if any close relatives have been diagnosed with cardiac disease. The symptoms of mitral valve stenosis are similar to a number of other heart conditions, including some that tend to run in families. Knowing as much as possible about your family's health history will help your doctor determine next steps for your diagnosis and treatment.

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

Tests and diagnosis

If you develop signs or symptoms of mitral valve stenosis for example, if you are suddenly breathless with mild exertion your doctor may ask you to undergo several types of diagnostic tests.

But first your doctor will ask about your medical history and give you a physical examination. As part of your examination, he or she listens carefully to your heart through a stethoscope. Mitral valve stenosis causes an abnormal heart sound, called a heart murmur. A narrowed mitral valve can make a distinct snapping sound followed by a rumbling murmur.

In addition to listening to your heart, your doctor listens to your lungs and the sounds of your breathing. Your doctor is checking for lung congestion the buildup of fluid in your lungs that can occur with mitral valve stenosis.

From the initial results, your doctor decides which tests are needed to make a diagnosis. For testing, you may be referred to a cardiologist.

Diagnostic tests
Common tests to diagnose mitral valve stenosis include:

  • Echocardiogram. This test uses sound waves to produce an image of your heart. In an echocardiogram, sound waves are directed at your heart from a wand-like device (transducer) held on your chest. Sound waves bounce off your heart and are reflected back through the chest wall and processed electronically to provide video images of your heart in motion. An echocardiogram helps your doctor closely examine the mitral valve. The image shows the structure of the mitral valve and how it moves during the beating of your heart.
  • Electrocardiogram (ECG). In this test, patches with wires (electrodes) are attached to your skin to measure the electrical impulses given off by your heart. Impulses are recorded as waves displayed on a monitor or printed on paper. An ECG can give information about your heart rhythm and, indirectly, heart size. With mitral valve stenosis, some parts of your heart may be enlarged and you may have atrial fibrillation, a heart rhythm irregularity. Your doctor may ask you to walk on a treadmill or pedal a stationary bike while undergoing an ECG, to see how your heart responds to exertion.
  • Holter monitoring. A Holter monitor is a portable device that you wear to record a continuous ECG, usually for 24 to 72 hours. Holter monitoring is used to detect intermittent heart rhythm irregularities that may accompany mitral valve stenosis.
  • Chest X-ray. An X-ray image of your chest allows your doctor to check the size and shape of your heart to determine whether the left atrium is enlarged - a possible indicator of mitral valve stenosis. A chest X-ray also helps your doctor check the condition of your lungs. Mitral valve stenosis may lead to blood backing up in your lungs, which causes congestion that's visible on an X-ray.
  • Transesophageal echocardiogram. This type of echocardiogram allows an even closer look at the mitral valve. Your esophagus, the tube that runs from your throat to your stomach, lies closely behind your heart. In a traditional echocardiogram, a transducer is moved across your chest. In a transesophageal echocardiogram, a small transducer attached to the end of a tube is inserted down your esophagus. Because your esophagus lies close to your heart, having the transducer there provides a clearer picture of the mitral valve and blood flow through it.
  • Cardiac catheterization. In this procedure, your doctor threads a thin tube (catheter) through a blood vessel in your arm or groin to an artery in your heart. A dye injected through the catheter fills your heart's arteries, and the arteries become visible on an X-ray. This test gives your doctor detailed information about the condition of your heart. Some catheters used in cardiac catheterization have miniature devices (sensors) at the tips that can measure pressure within heart chambers, such as the left atrium.

Cardiac tests such as these help your doctor distinguish mitral valve stenosis from other heart conditions, including other problems of the mitral valve. Mitral regurgitation is a condition in which the mitral valve doesn't close tightly. Mitral valve prolapse is a disorder in which the mitral valve sags instead of closing tightly. These conditions may also require treatment.

If you receive a diagnosis of mitral valve stenosis, these tests also help reveal the cause, determine how serious the problem is, and determine whether the mitral valve can be repaired or if replacement may be necessary.

Treatments and drugs

Treatments to prevent permanent damage to your heart from mitral valve stenosis include medications and invasive procedures.

Invasive treatment for mitral valve stenosis isn't always needed right away. If tests reveal that you have mild to moderate mitral valve stenosis and you have no symptoms, there's generally no need for immediate valve repair or replacement. Instead, your doctor will schedule checkups to carefully monitor the valve so that surgery can be done if your condition becomes more severe. Some people never need anything done to the mitral valve because they never develop severe mitral valve stenosis.

Medications
No medications can correct a defect in the mitral valve. However, certain drugs can reduce symptoms by easing your heart's workload and regulating your heart's rhythm.

For example, your doctor may prescribe:

  • Diuretics. These drugs can reduce fluid accumulation in your lungs or elsewhere.
  • Blood thinners (anticoagulants). These medications help to prevent blood clots from forming.
  • Beta blockers or calcium channel blockers. These medications may be used to slow your heart rate and allow your heart to fill more effectively.
  • Anti-arrhythmic medications. These medications may be used to treat atrial fibrillation or other rhythm disturbances associated with mitral valve stenosis.

Procedures
You may need valve repair or replacement to treat mitral valve stenosis. Both surgical and nonsurgical options are available.

Repair with balloon valvuloplasty (valvotomy)
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 your heart and into your narrowed mitral valve. Once in position, a balloon at the tip of the catheter is inflated. The balloon pushes open the mitral valve and stretches the valve opening, improving blood flow. The balloon is then deflated and the catheter with balloon is guided back out of your body. Balloon valvuloplasty can relieve mitral valve stenosis and its symptoms. But it may not be appropriate if the valve is both tight (stenotic) and leaky (regurgitant) or if your valve is too heavily calcified. It's also not performed if there's a blood clot in a chamber of your heart, because of the risk of dislodging it. You may need the procedure repeated.

Mitral valve surgery
If there is more than mild leakage (regurgitation) of your valve or if you have other valve problems in addition to mitral stenosis, surgery may be a better option than balloon valvuloplasty. Surgical options include:

  • Valvuloplasty. Using traditional surgical tools, a cardiac surgeon may make repairs such as separating fused valve leaflets and removing obstructions on or near the mitral valve. This helps clear the valve passageway. You may need the procedure repeated if you develop mitral valve stenosis again in the years following surgery.
  • Mitral valve replacement. Most people with mitral valve stenosis who need surgery will have mitral valve replacement. Your surgeon removes the narrowed mitral valve and replaces it with a mechanical valve or a tissue valve. Mechanical valves, made from metal, are durable, but they carry the risk of blood clots forming on or near the valve. 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 cadaver donor often eventually need to be replaced. Your doctor can discuss the risks and benefits of each type of heart valve with you.

You may continue to be at risk of arrhythmias even after successful surgery for mitral valve stenosis. You may need to take medications to lower that risk or control your heart rate.

Other procedures
In some cases your surgeon may perform additional surgery at the time of your operation to try to keep your heart in normal rhythm, such as the maze procedure. This involves making a series of surgical incisions in the upper half of your heart (atria). These heal into carefully placed scars in the atria that form boundaries that force electrical impulses in your heart to travel properly to cause the heart to beat efficiently.

Lifestyle and home remedies

To improve your quality of life if you have mitral valve stenosis, your doctor may recommend that you:

  • See your dentist regularly. Receive regular dental care, following recommendations for the prevention of heart infections (endocarditis) for any dental procedure.
  • Lower the salt in your diet. Food doesn't directly affect the degree of mitral valve stenosis. However, salt in food and drinks may increase the pressure on your heart. So don't add salt to your food, and avoid foods high in sodium. Read the labels on foods for sodium content and ask for low-salt foods when you eat out.
  • Maintain a healthy weight. Excess weight may make you short of breath and may complicate heart surgery if you ever need it. Keep your weight within a range recommended by your doctor.
  • Cut back on caffeine. Irregular heartbeats (arrhythmias) may occur in people with mitral valve stenosis. Arrhythmias may get worse if you have too much caffeine. 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 can make symptoms worse. If you have mitral valve stenosis, ask your doctor about the effects of drinking alcohol.
  • Exercise. Physical activity may help to keep your body fit and may help you to recover faster if you ever need heart surgery. How long and hard you're able to exercise may depend on what level of activity triggers your symptoms, if any. Ask your doctor for guidance before starting any exercise program.
  • See your doctor regularly. Establish a regular appointment schedule with your cardiologist or primary care provider.

If you're a woman with mitral valve stenosis, discuss family planning with your doctor before you become pregnant, because your heart works harder during pregnancy. How a heart with mitral valve stenosis tolerates this extra work depends on the degree of stenosis and how well your heart pumps. If you become pregnant, your cardiologist and obstetrician should evaluate you throughout your pregnancy, labor and delivery, and after delivery.

Prevention

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 when any of you have a sore throat. Untreated strep throat infections can develop into rheumatic fever. Fortunately, strep throat is usually easily treated with antibiotics.

Updated: 9/15/2011

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