Mitral stenosis

Alternative names:

mitral valve obstruction

Definition:

A disorder characterized by narrowing or obstruction of the mitral valve, which prevents the valve from opening properly.

Causes, incidence, and risk factors:

Mitral stenosis is a heart valve disorder that affects about 2 out of 10,000 people. Symptoms usually develop between the ages of 20 and 50. It most commonly occurs in people who have had rheumatic fever but can be caused by any disorder that causes narrowing of the mitral valve. Congenital mitral stenosis alone is rare. It more commonly occurs with complex groups of cardiac abnormalities.

Narrowing of the mitral valve obstructs blood flow from the left atrium to the left ventricle. This can reduce the amount of blood that flows forward to the body. The atrium enlarges as pressure builds up in it, and blood may backflow into the lungs resulting in pulmonary edema (fluid in the lung tissue).

Risk factors include a history of rheumatic fever, stroke, or certain other disorders. Symptoms may begin with an episode of atrial fibrillation, or may be triggered by pregnancy or other stress on the body such as respiratory infection, endocarditis, and other cardiac disorders.