Restrictive cardiomyopathy with complete atrioventricular block and distal myopathy with rimmed vacuoles.

Two-dimensional echocardiography, cardiac catheterization, electrophysiologic studies, and biopsies of cardiac and skeletal muscle were performed in a patient with complete atrioventricular block as the initial manifestation of restrictive cardiomyopathy. The patient also showed distal myopathy with rimmed vacuoles. Weakness of the distal leg muscles occurred several years after the initial cardiac manifestations and the patient developed congestive heart failure 1 year before the second admission. Endomyocardial biopsy showed patchy myocardial fibrosis without endomyocardial fibrosis or any other specific findings of myocardial disease. Histochemical examination of skeletal muscle showed the typical features of distal myopathy with rimmed vacuoles. In some patients with atrioventricular block as the initial manifestation of restrictive cardiomyopathy, the cardiomyopathy may be just 1 manifestation of a more generalized disorder affecting both cardiac and skeletal muscle.