Mitral valve systolic click syndrome.

Mitral valve prolapse, although usually a benign condition, can cause incapacitating chest pain or refractory arrhythmias. Among patients undergoing cardiac catheterization for evaluation of chest pain, 50 who were found to have mitral valve prolapse were analyzed. Three patients had neither a click nor a murmur. Echocardiography was diagnostic in 46 patients; two patients had no evidence of prolapse, and two patients had tests that were technically inadequate. Only 15 of the patients demonstrated a normal electrocardiogram.