Mid-systolic click and mitral valve prolapse following mitral commissurotomy.

Five patients with rheumatic mitral stenosis were observed to have mid-systolic clicks with murmurs of mitral regurgitation at various intervals after mitral commissurotomy. In two patients echocardiography showed an unusually rapid posterior deflection of the mitral valve coinciding exactly with a systolic nonejection click. It is speculated that the shortened, fused chordae tendineae, compromised by mitral commissurotomy, rigidly hold the valve leaflets fixed at the onset of systole. During systole, ventricular conformational changes, in the face of marginal coaptation of thickened and fibrotic mitral leaflets, allow the mitral valve to be forced abruptly towards the left atrium with great velocity. This is manifested by a loud systolic click and, in some patients, a near vertical posterior systolic deflection of the mitral valve on the echocardiogram. The systolic click may occur without echocardiographic or angiographic evidence of mitral valve prolapse. Unusually loud mid-systolic clicks can be heard in patients with rheumatic heart disease after mitral commissurotomy and may be accompanied by a distinctive echocardiographic appearance of the mitral valve.