A 49 year old man presented with atypical chest pain for five months. He had no risk factors for atherosclerosis. Exercise electrocardiography was stopped prematurely because of leg cramp. Coronary angiography was performed and revealed normal left ventricular function. Left and right coronary angiography did not show any evidence of luminal narrowing or occlusion of either coronary artery (below left). However, with the selective injection of the right coronary artery (RCA) in a left anterior oblique view, the …