AbstractA 64‐year‐old woman presented with acute congestive heart failure and atrial fibrillation, with good response to medical management. Selective coronary and left ventricular cineangiography demonstrated multiple arteriosystemic connections arising from both left and right coronary arteries, but normal (although tortuous) coronary vessels and ventricular contraction pattern. Determination of the magnitude of the shunt flow and concommitant measurement of myocardial lactate extraction suggested that this type of coronary vascular abnormality was an angiographic curiosity without discernible clinical import; however, the etiology of the patient's heart disease remains an eni