Mitral valve stenosis

DEFINITION

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.

CAUSES

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.

SYMPTOMS

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.

If you’ve been diagnosed with mitral valve stenosis but haven’t had symptoms, talk to your doctor about follow-up evaluations.