Mitral Stenosis[MS] is the narrowing of the mitral valve causing hindrance to the blood flow. The normal mitral valve orifice is about 4 to 6 cm2. When this area becomes less than 2 cm2 , a pressure gradient across the valve develops. As the gradient increases the time for ventricles to fill increases; resulting in increased heart rate, reduced cardiac output and pulmonary hypertension. The constant increase in the left atrial pressure causes pulmonary congestion and dilates the left atrium. Patients are prone to develop atrial fibrillation and heart failure.
Mitral stenosis is termed severe when the valve area is less than 1 cm2. Mitral stenosis is more common in women than in men. Symptoms usually occur in or after the third decade of life and its progression is higher in developing countires compared to the developed western countries.