A rare anomaly of LAD mimicking CTO.

A 65-year-old man was admitted into our hospital because of the detailed examination for abnormal Q waves in inferior leads on an electrocardiogram. Coronary angiography and 320-row area detector computed tomography (ADCT) revealed "dual left anterior descending artery (LAD)", which was a rare anomaly of the LAD and chronic total occlusion (CTO) at segment 2 of the right coronary artery (RCA). The course of the anomalous LAD arising from the proximal portion of the RCA was specifically identified between aortic root and right ventricular outflow tract (RVOT) by 320-row ADCT. The anomalous LAD had potential risk of myocardial ischemia because of the compression from aortic root and RVOT during exercise. We performed technetium myocardial perfusion scintigram to evaluate exercise-induced ischemia in the territory of the anomalous LAD and to decide therapeutic strategies including coronary artery bypass grafting surgery to the vessel. The scintigram revealed no exercise-induced ischemia in anteroseptal wall and a constant perfusion defect in posteroinferior wall of the left ventricle. Thus, we decided to treat the patient with pharmacological treatment in the outpatient setting. This report suggests that it is important to recognize the variants of coronary arteries for optimal treatment. <Learning objective: Coronary artery anomalies such as "dual left anterior descending artery" are particularly rare. Anomalous coronary artery may contribute to exercise-induced myocardial ischemia and sudden cardiac death by the compression of the great arteries even when coronary angiography revealed no fixed stenosis in the artery. We have to recognize the types, clinical features and functional properties of the coronary artery anomalies for preventing misdiagnosis of coronary angiogram and deciding the best treatment for patients.>.