The mitral valve is located on the left side of your heart, between two chambers: the atrium and the ventricle. The atrium is the upper chamber, and the ventricle is the lower chamber. Blood is pumped from the left atrium, through the mitral valve, and into the left ventricle on its way to the aorta. The healthy mitral valve allows blood to pass through, but prevents it from flowing back. See a BodyMap of the mitral valve here.

Mitral valve stenosis, also known as mitral stenosis, occurs when the mitral valve opening is narrowed. This means that not enough blood can flow through it.

Mitral valve stenosis can lead to a variety of issues, including fatigue, difficulty breathing, blood clots, and heart failure.

Scarring caused by rheumatic fever is the leading cause of mitral valve stenosis. Although rheumatic fever is common in some countries, it’s become rare in the United States due to early recognition and treatment of streptococcal infections.

Mitral valve stenosis is typically caused by rheumatic fever. This is usually a childhood disease. Rheumatic fever results from the body’s immune response to an infection with the streptococcal bacteria. It is a serious complication of strep throat or scarlet fever.

The joints and the heart are the organs most affected by acute rheumatic fever. The joints can become very inflamed and can lead to temporary and sometimes chronic disability. During acute rheumatic fever, various parts of the heart can become inflamed, leading to:

  • Endocarditis. This disorder affects the heart’s lining (called the endocardium).
  • Myocarditis. This disease affects the heart muscle (called the myocardium).
  • Pericarditis. This condition affects the membrane surrounding the heart (called the pericardium).

When the mitral valve or any of the heart valves becomes involved, it leads to a chronic heart condition called rheumatic heart disease. The clinical signs and symptoms of this condition might not occur until 5 to 10 years after the episode of rheumatic fever.

In 2005, the journal Circulation noted that most cases of mitral stenosis in the United States were found in people who had moved from countries where rheumatic fever is common.

Risk factors for the condition are unclear. However, it’s estimated that women are two to three times more likely than men to develop the condition.

A congenital heart defect may cause mitral valve stenosis in a baby. Babies born with this condition usually need surgery, according to the medical journal Research in Cardiovascular Medicine.

In rare cases, calcium may build up and lead to narrowing of the mitral valve. Other rare causes of mitral valve stenosis include:

Mitral valve stenosis commonly leads to shortness of breath, especially during exercise or when lying down.

Other common symptoms include:

In rare instances, you may feel discomfort in your chest. Your chest might feel tight or constricted, or you may feel pain that radiates outward from your chest.

In some cases, mitral valve stenosis may not cause any symptoms, or the symptoms may appear only during exercise. You might develop symptoms when your body undergoes stress such as during an infection or pregnancy.

In addition to the common symptoms, children with mitral valve stenosis might also experience slower growth.

There are several tests that your doctor may use to diagnose mitral valve stenosis.

Physical exam

Your doctor will listen to your heart with a stethoscope. In people with this condition, the heart often makes unusual sounds such as rumbling and snapping. According to the Mayo Clinic, a heart murmur, arrhythmia, and fluid in the lungs are all indicators of mitral valve stenosis.

Imaging tests

Your doctor may use a variety of imaging tests to confirm diagnosis, as well as to deduce the original cause of the problem. These tests may include:

  • Echocardiogram. This test uses ultrasound waves to produce live images of your heart’s structure and function. It’s by far the most commonly used diagnostic test for mitral valve stenosis.
  • Chest X-ray. This imaging test uses small amounts of radiation to produce images of your heart and lungs.
  • Transesophageal echocardiogram (TEE). In this imaging test, your doctor threads a small device into your esophagus that emits ultrasound waves. This method creates a more detailed picture than an echocardiogram because the esophagus is right behind the heart.
  • Cardiac catheterization. In this procedure, your doctor inserts a long, thin tube into your arm, upper thigh, or neck, and threads it to your heart. The doctor can use this tube to run a variety of tests, including getting an image of your heart’s blood vessels. This procedure is the most invasive and risky, but also the most accurate.

Tests for heart rhythm irregularities

Tests that can monitor your heart for rhythm abnormalities include the electrocardiogram and Holter monitoring. The electrocardiogram also known as an ECG or EKG is a recording of your heart’s electrical activity. During Holter monitoring, your heart’s electrical activity is recorded using a portable monitoring device worn over a period of time. You’re usually monitored for a period of 24 to 48 hours.

Stress tests

Your doctor may have you perform moderate aerobic activity, and then monitor you while you exercise to determine how your heart responds to physical stress. Learn more about stress tests here.

Treatment for mitral valve stenosis can vary greatly, depending on your symptoms and the severity of the condition. If you have no symptoms and only mild mitral valve stenosis, you might not need any treatment.

Drugs and medication

If your mitral valve stenosis is causing symptoms, your doctor might prescribe medications. Although medications do not fix the problem with your mitral valve, they can help treat your symptoms. Types of medications your doctor might prescribe include:

Valvuloplasty

Your doctor may choose to perform a mitral balloon valvuloplasty. This procedure is an option if you need more treatment than just medication, but your mitral valve isn’t damaged enough to require heart surgery. During this procedure, your doctor threads a catheter with a balloon attached to it through a vein and into your heart. Once in the mitral valve, the doctor inflates the balloon to expand the valve. In some cases, you may need to undergo this procedure more than once.

Surgery

In some cases, surgery may become necessary. Your doctor may surgically repair your existing mitral valve to make it function properly. If that isn’t possible, your doctor may need to replace your mitral valve with a new one. Your replacement valve may be biological, meaning, it comes from a cow, pig, or human cadaver. Or it may be mechanical, meaning your valve is a man-made device.

If undetected or untreated, mitral valve stenosis can result in serious complications. The most common one is arrhythmia. Atrial fibrillation, in which the upper chambers of the heart tremble, will develop in many cases.

Endocarditis and heart failure can also occur.

Mitral valve stenosis also affects the lungs. Pulmonary edema, or fluid buildup, and pulmonary arterial hypertension may develop as a result of mitral valve stenosis.

Although lifestyle changes can’t repair mitral valve stenosis, they may ease your symptoms or help keep the problem from worsening.

Your doctor might suggest that you make changes to your diet. These typically involve consuming less:

You should reach or maintain a weight that is healthy for you. Your doctor may instruct you to exercise to help you get or stay fit. However, your exercise regimen must take your condition into account. Exercising too vigorously may cause your symptoms to flare up.