mitral stenosis

Think of a funnel whose neck has narrowed so the liquid above it cannot drain away freely and instead backs up. In mitral stenosis the mitral valve — between the left atrium and left ventricle — is narrowed and stiff, so blood cannot flow easily from atrium to ventricle during the heart's filling phase, and pressure builds up behind it.

That rising pressure is transmitted backward into the left atrium, then into the lung circulation. The result is breathlessness, especially on exertion or when lying flat, and sometimes coughing up blood-tinged sputum. The strained left atrium tends to enlarge and develop atrial fibrillation, which in turn raises the risk of clot formation and stroke.

By far the leading cause worldwide is rheumatic heart disease, the late consequence of childhood rheumatic fever, which fuses and thickens the valve leaflets. Diagnosis rests on a characteristic low-pitched rumbling diastolic murmur at the apex and on echocardiography, which measures the valve area. Treatment ranges from rate control and anticoagulation to opening the valve by balloon valvuloplasty or replacing it.

This is general educational information; rheumatic mitral disease in particular requires individualized specialist management.