Anomalous right coronary artery originating from the mid left anterior descending artery

A 68-year-old male with a history of hypertension and hypercholesterolemia presented with recurrent episodes of chest discomfort. A 12-lead ECG and an echocardiogram were normal. A myocardial perfusion study could not rule out ischemia in the inferior wall. At coronary angiography using the transradial approach, the right coronary artery (RCA) could not be visualized. Angiography of the left coronary system demonstrated non-obstructive atherosclerosis involving the mid segment of the left anterior descending (LAD) artery and a normal circumflex (Cx) artery. The RCA originated from the mid LAD segment distal to the first septal perforator and the first diagonal branch and was free of atherosclerosis disease. A contrast-enhanced 64-slice multi-detector cardiac computed tomography showed that the LAD was severely calcified in the proximal part, and the RCA coursed anterior to the right ventricular outflow tract (RVOT) to reach the right atrioventricular groove. The patient was managed medically and became asymptomatic.