Definition of Mitral stenosis:

Mitral stenosis is a heart valve disorder that involves a narrowing or blockage of the opening of the mitral valve, which separates the upper and lower chambers on the left side of the heart.

Causes, incidence, and risk factors:

Mitral stenosis prevents the valve from opening properly. This prevents proper blood flow from moving between the left atrium (upper chamber of the heart) and ventricle (lower chamber of the heart). As the valve area becomes smaller, less blood flows forward to the body. The upper heart chamber swells as pressure builds up and blood may flow back into the lungs, resulting in pulmonary edema (fluid in the lung tissue).

In adults, mitral stenosis most commonly occurs in people who have had rheumatic fever. Since rheumatic fever rates are declining in the United States, the rate of mitral stenosis is also decreasing. Only rarely do other disorders cause mitral stenosis in adults.

In children, congenital mitral stenosis is more often part of a group of heart deformities.

In children, mitral stenosis may run in families.