Arterilization of the coronary venous system has been suggested as a means of myocardial perfusion. We recently studied a patient with a saphenous vein aorto=coronary venous bypass graft created inadvertently during surgery intended to bypass the anterior descending artery. We selectively injected onctrast into this graft during balloon occlusion of the coronary sinus both before and after sublingual nitroglycerin. No arterial visualization was demonstrated from the vein and no evidence to suggest perfusion of the myocardium was found.