A syndrome of congenital cardiomyopathy with mitral regurgitation, complete heart block and atrial arrhythmia

Abstract

A distinctive syndrome of cardiomyopathy with mitral regurgitation, complete heart block and atrial arrhythmia was noted in four male patients aged 19 to 49 years. Each presented with cardiac enlargement and varying degrees of left ventricular failure. One patient was known to have had complete heart block from infancy and another patient from 13 years of age. Each had chronic atrial fibrillation or flutter, with a regular ventricular rhythm at 35 to 45/min. Hemodynamic studies showed dilatation and poor contractility of the left ventricle, considerable mitral regurgitation, reduced resting cardiac output and elevated left ventricular end-diastolic pressures. The clinical course in follow-up periods of up to 5 years has been one of relatively mild, slowly progressive congestive heart failure. Mitral valve replacement and permanent pacemaker installation in one patient had no effect on the clinical course. The mitral valve showed redundant leaflet tissue with mucoid degenerative changes. This syndrome appears to represent a form of congenital cardiomyopathy which involves degeneration or fibrotic changes in both the myocardium and the conduction system. Familial occurrence has not been recognized.