Health Library

Mitral Valve Stenosis

This valve acts like a door, allowing blood to flow from the left atrium, a collecting chamber at the top of the heart, to the left ventricle, the pumping chamber at the bottom of the heart. When the mitral valve is too narrow, it restricts blood flow.

Untreated mitral valve stenosis can cause multiple health issues like irregular heartbeats, blood clots, high blood pressure in the lungs and heart failure.

Mitral Valve Conditions

• Mitral valve stenosis —When the mitral valve is too narrow.
• Mitral valve regurgitation—When the mitral valve leaks, allowing blood to flow backward. Like mitral valve stenosis, it can also cause problems because the heart has to work harder to pump blood.
• Mitral valve prolapse—When one of the valve’s flaps, which works like a hinge on a door, doesn’t close properly. This is more common in adults. It usually leads to regurgitation, not stenosis.

What Causes Mitral Valve Stenosis?

Some people have congenital mitral valve stenosis (present at birth). For others, it develops later in life. The exact cause of congenital mitral valve stenosis is not known. There is a greater chance that a baby will be born with mitral valve stenosis if someone else in the family has had it.

Some people are born with a damaged mitral valve. This may lead to stenosis as they age.

Conditions like rheumatic fever, which can occur after untreated strep throat, can damage the heart valves. This can lead to stenosis. Endocarditis, an infection of the heart’s inner lining, also can lead to mitral valve damage and stenosis and regurgitation.

What are the Symptoms of Mitral Valve Stenosis?

Many children with mitral valve stenosis don’t show signs at first. The most common symptoms of mild stenosis are rapid breathing, slowed growth and a slight heart murmur.

As stenosis gets worse, symptoms may become more noticeable. These symptoms may not appear right away and can develop slowly over time:

• Shortness of breath, especially during physical activity
• Fatigue or needing rest often
• Frequent coughing or wheezing
• Chest pain

For example, children who have not yet been diagnosed with mitral valve stenosis may need more breaks during activities like soccer. They might tire more easily and not be able to keep up with friends.

How is Mitral Valve Stenosis Diagnosed?

The discovery of a heart murmur during a doctor’s exam is often the first step to diagnosis. A murmur is a specific sound that doctors can hear when they listen to your child’s heart with a stethoscope. This sound happens because as blood flows through a narrow mitral valve, it creates a low-pitched, rumbling noise. This sound is known as a mitral valve stenosis murmur. It’s typically heard during diastole, the heart’s relaxation phase. The sound is most noticeable over the lower part of the heart called the apex.

A doctor may do other tests to diagnose mitral valve stenosis.

• An echocardiogram (ECHO) is an ultrasound test used to diagnose mitral valve stenosis. It gives detailed images of the heart’s structure and function.
• An electrocardiogram (EKG) records the heart’s electrical activity. It shows if the heart chambers are enlarged.
• A chest X-ray can show changes in the heart or lungs. Changes might suggest mitral valve stenosis.

EKG and chest X-rays are sensitive tests, but if more details are needed, an ECHO is used to confirm mitral valve stenosis.

How is Mitral Valve Stenosis Treated?

Treatment depends on the mitral valve stenosis severity and the symptoms.

Stenosis is considered mild when there’s only a small amount of narrowing of the valve. You might not notice any problems. Your child can do their usual activities. Even with mild stenosis, your child should see a heart doctor regularly to ensure their symptoms don’t get worse. A heart doctor is called a cardiologist. If your child’s symptoms get worse, your doctor can consider medicines or treatments to treat mitral valve stenosis.

In severe mitral valve stenosis, surgery might be needed to repair or replace the mitral valve. Repair involves fixing the existing valve. Replacement involves using a mechanical (man-made) or biological (from an animal) valve. After surgery, patients usually recover in a cardiac intensive care unit and need lifelong follow-up with a cardiologist.

Mitral Valve Stenosis Risk Factors for Operations

Mitral valve stenosis surgery has a risk of infection, bleeding and potential damage to other structures in your body. It’s possible the mitral valve could leak after surgery, and another surgery could be needed to replace it.

Children with a replacement valve typically need another surgery later in life because the valve doesn’t grow with the child. Your child’s age and how fast they grow will help your doctor decide when another valve replacement is needed.

Mitral Valve Stenosis Complications

If left untreated, mitral valve stenosis can cause:

• A feeling of being out of breath, particularly with activity
• Increased pressure in the left atrium, leading to lung damage
• Damage to the right side of the heart due to increased pressure

Imagine you put your finger over the end of a hose. It would create pressure that builds into the back part of the hose. Similarly, if the mitral valve in the heart is narrow, pressure pushes back into the lungs. If this pressure isn’t treated for a long time, it can damage the lungs. Since the lungs are connected to the right side of the heart, it can lead to heart problems.

Mitral Valve Stenosis Prognosis

With proper treatment, many children can return to normal activities, though they may have some limitations. Continued follow-up with a cardiologist is essential to manage the condition and prevent further complications.