The mitral valve separates the upper and lower chambers on the left side of the heart. Stenosis is a condition in which the valve does not open fully, restricting blood flow. Mitral stenosis is a disorder in which the mitral valve does not open fully.
Mitral valve obstruction
Blood that flows between different chambers of your heart must flow through a valve. The valve between the two chambers on the left side of your heart is called the mitral valve. It opens up enough so that blood can flow from the upper chamber of your heart (left atria) to the lower chamber (left ventricle). It then closes, keeping blood from flowing backwards.
Mitral stenosis means that the valve cannot open enough. As a result, less blood flows to the body. The upper heart chamber swells as pressure builds up. Blood and fluid may then collect in the lung tissue (pulmonary edema), making it hard to breathe. See also: heart failure.
In adults, mitral stenosis occurs most often in those who have had rheumatic fever (a condition that may develop after untreated or poorly treated strep throat or scarlet fever). The valve problems develop 5 - 10 years or more after the episode of rheumatic fever, and symptoms may not show up for even longer. Rheumatic fever is becoming rare in the United States due to treatment of strep infections, so mitral stenosis is also less common.
Only rarely do other factors cause mitral stenosis in adults. These include:
- Calcium deposits forming around the mitral valve
- Radiation treatment to the chest
- Some medications
Children may be born with mitral stenosis (congenital) or other birth defects involving the heart that cause mitral stenosis. Often, there are other heart defects present with the mitral stenosis.
Mitral stenosis may run in families.
In adults there may be no symptoms. However, symptoms may appear or get worse with exercise or any activity that raises the heart rate. In adults, symptoms usually develop between ages 20 and 50.
Symptoms may begin with an episode of atrial fibrillation (especially if it causes a fast heart rate). They may also be triggered by pregnancy or other stress on the body, such as infection in the heart or lungs, or other heart disorders.
Symptoms may include:
- Chest discomfort (rare)
- Increases with activity, decreases with rest
- Radiates to the arm, neck, jaw, or other areas
- Tight, crushing, pressure, squeezing, constricting
- Cough, possibly bloody (hemoptysis)
- Difficulty breathing during or after exercise or when lying flat; may wake up with difficulty breathing (most common symptom)
- Fatigue, becoming tired easily
- Frequent respiratory infections such as bronchitis
- Sensation of feeling the heart beat (palpitations)
- Swelling of feet or ankles
In infants and children, symptoms may be present from birth (congenital), and almost always develop within the first 2 years of life. Symptoms include:
- Poor feeding or sweating when feeding
- Poor growth
- Shortness of breath
Exams and Tests
The health care provider will listen to the heart and lungs with a stethoscope. A distinctive murmur, snap, or other abnormal heart sound may be heard. The typical murmur is a rumbling sound that is heard over the heart during the resting phase of the heartbeat. The sound often gets louder just before the heart begins to contract.
The exam may also reveal an irregular heartbeat or lung congestion. Blood pressure is usually normal.
Narrowing or blockage of the valve or swelling of the upper heart chambers may be seen on:
Treatment depends on the symptoms and condition of the heart and lungs. People with mild symptoms or none at all may not need treatment. For severe symptoms, you may need to go to the hospital for diagnosis and treatment.
Medications are used to treat symptoms of heart failure or abnormal heart rhythms (most commonly atrial fibrillation) and high blood pressure, as well as to prevent blood clots.
- These include diuretics (water pills), nitrates, beta-blockers, calcium channel blockers, ACE inhibitors, angiotensin receptor blockers (ARBs), or digoxin.
- Anticoagulants (blood thinners) are used to prevent blood clots from forming and traveling to other parts of the body.
Antibiotics may be used for some people with mitral stenosis:
- People who have had rheumatic fever may need long-term preventive treatment with penicillin.
- In the past, most patients with heart valve problems such as mitral stenosis were given antibiotics before dental work or invasive procedures, such as colonoscopy. The antibiotics were given to prevent an infection of the damaged heart valve. However, antibiotics are now used much less often before dental work and other procedures. Ask your doctor whether you need to use antibiotics.
Some patients may need heart procedures to treat mitral stenosis. Percutaneous mitral balloon valvotomy (also called valvuloplasty) may be tried instead of surgery in people with a less damaged mitral valve. During this procedure, a tube (catheter) is inserted into a vein, usually in the leg. It is threaded up into the heart. A balloon on the tip of the catheter is inflated, widening the mitral valve and improving blood flow.
Other people need to have the mitral valve repaired or replaced. Replacement valves can be made from different materials. Some may last for decades and others can wear out and need to be replaced.
For more information, see:
Children often need surgery to either repair or replace the mitral valve.
The outcome varies. The disorder may be mild, without symptoms, or may be more severe and eventually disabling. Complications may be severe or life threatening. Mitral stenosis is usually controllable with treatment and improved with valvuloplasty or surgery.
When to Contact a Medical Professional
Call your health care provider if:
- You have symptoms of mitral stenosis
- You have mitral stenosis and symptoms do not improve with treatment, or new symptoms appear
Follow your health care provider's recommended treatment for conditions that may cause valve disease. Treat strep infections promptly to prevent rheumatic fever. Tell your health care provider if you have a family history of congenital heart diseases.
Mitral stenosis itself often cannot be prevented, but complications can be prevented. Tell your health care provider about your heart valve disease before you receive any medical treatment. Discuss whether you need preventive antibiotics.
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David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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