Appearance of or persistence of severe mitral regurgitation without left ventricular outflow obstruction after partial ventricular septal myotomy-myectomy in hypertrophic cardiomyopathy

At the National Heart, Lung, and Blood Institute from 1959 through October 1989, 626 patients underwent operative treatment of obstructive hypertrophic cardiomyopathy: ventricular septal myotomy-partial myectomy alone in 539 patients; mitral valve replacement alone in 68 patients; and both procedures, not necessarily simultaneously, in 27 patients. The septal myotomy-myectomy procedure in most patients provided clinical improvement, but in some patients the results of this procedure have been unsatisfactory and reoperation has been performed.¹ In the 27 patients who underwent reoperation after septal myotomy-myectomy, the indication was persistent left ventricular outflow obstruction in 24 patients² and pure mitral regurgitation, without outflow obstruction, in 3 patients. This report describes certain clinical and morphologic features in the latter 3 patients.