Congenital right coronary artery (RCA) abberant arises from left circumflex artery (LCX).

Female, 55 year old with history of long standing hypertension and diabetes, came to ER in a hospital with decreased consciousness. The pulse was irregular and ECG showed recurrent Ventricular Tachycardia (VT). After immediate intervention, she was finally survived and admitted to Intensive coronary care Unit (ICCU). Cardiac troponin was positive. She was considered to have acute coronary syndrome. The Brain CT showed ischemic lesion. During hospitalization, coronary angiography was performed. It showed left dominant coronary artery and very small right coronary artery (RCA) with no RCA ostial at the aorta. There was 50% stenosis in Left Descending Artery (LAD) and 30% in Left Circumflex (LCX). Total occlusion caused by thrombus at the RCA ostial was suspected. The cardiac MSCT was then performed to confirm the result. The MSCT showed no ostial of RCA at aorta and suspected total occlusion in proximal RCA. The RCA arises from LCX and its vessel was small in diameter less than 2 mm.