Etiology of isolated mitral regurgitation: a clinico-echocardiographic study.

One hundred and ninety two consecutive patients with isolated mitral regurgitation (MR) with an audible murmur were studied for determination of etiology. There were 95 males & 97 females (mean age 24.5 +/- 10.8 years; range 13 to 58 years) with 102 patients in NYHA classes I and II, 81 in class III and 9 in NYHA class IV. The etiological grouping was: rheumatic 74 (38.5%), probable rheumatic 28 (15%), mitral valve prolapse 26 (13.5%), dilated cardiomyopathy 15 (8%), infective endocarditis 12 (6%), isochaemic heart disease 10 (5%), miscellaneous group (including rupture chordae tendinae, aortoarteritis etc) 9 (4.5%) and patients with indeterminate etiology 18 (9.5%). Etiology could be determined in 174 out of 192 cases. The clinical methods combined with echocardiography were helpful in 79 cases while echocardiography alone could diagnose etiology in 89 cases. Clinical features alone gave the diagnosis in 6 patients. The findings of gross morphology of the surgically removed mitral valves in 30 patients of this study were similar to their pre-operative etiologic diagnosis based on clinical and echocardiographic features. These findings may be of value in planning treatment and prophylactic strategies in cases of isolated MR.