Rheumatic mitral regurgitation

Rheumatic mitral regurgitation is caused by rheumatic fever involving the mitral valve. The most common lesion is fibrosis and thickening of the valve leaflets, commissural fusion, and narrowing of the valve orifice, forming pure mitral stenosis. Approximately one-third of cases have mitral stenosis accompanied by regurgitation. Pure mitral regurgitation is relatively rare, accounting for only about 5% of rheumatic mitral valve disease.