A young Black man with many features of pseudoxanthoma elasticum (PXE), confirmed by skin biopsy, complained of classic angina pectoris, decreasing effort tolerance, and palpitations. Clinically he was in severe congestive cardiac failure which was confirmed by echocardiography and cardiac catheterization, investigations which indicated the presence of a 'congestive' cardiomyopathy. Selective coronary arteriography showed normal epicardial vessels. Antemortem endomyocardial biopsy in this condition is described for the first time in the literature. This showed abnormal light microscopic and electron microscopic features. It is postulated that the predominant cause of congestive cardiac failure and angina pectoris in this disease is a diffuse arteriopathy secondary to elastic fibre dysgenesis, involving the small intramural coronary vessels ('small-vessel disease'). Hitherto it has been accepted that the endocardial changes have been most important in the pathophysiology. A review of the literature as it applies to cardiac involvement in PXE is undertaken.