Mitral stenosis is a narrowing of the mitral valve in the heart. This valve is located between the upper chamber and the lower pumping chamber of the left side of the heart. Blood must flow from the atrium, through the mitral valve, and into the ventricle before being pumped out into the rest of the body. Mitral stenosis can result in poor blood flow between the 2 left chambers, which can affect how much blood and oxygen is getting to the body's organs and tissues.

Mitral Valve Stenosis
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The most common cause of mitral stenosis is rheumatic fever, which scars the mitral valve. Less commonly, there are some congenital heart defects which may affect the mitral valve and its function. Very rare causes include bacterial endocarditis, blood clots, tumors, or other growths that block blood flow through the mitral valve.