Sunday, August 23, 2009

Mitral Stenosis

Mitral stenosis is a heart condition in which the mitral valve orifice is abnormally too narrow for an efficient blood flow. The mitral valve opens during left ventricular diastole to let blood flow from the left atrium (upper left chamber) to the left ventricle (lower left chamber). When a person suffers from mitral stenosis, the mitral valve does not open completely; in order to pump the same amount of blood the left atrium needs a higher pressure than normal to overcome the increased gradient. As a result, the left atrium swells when pressure builds up, increasing the risk of blood flowing back into the lungs; this could cause pulmonary edema.

Usually mitral stenosis is caused by rheumatic fever. But less common causes of mitral stenosis are calcification of the mitral valve flaps, and congenital malformation of the heart valves.