Septal course of left anterior descending artery from the right aortic sinus in tetralogy of Fallot: a benign anomaly and important lessons learned.

The proximal course of an anomalously arising coronary artery is a decisive factor in the surgical approach for tetralogy of Fallot (TOF). Studies have shown that echocardiography provides a good anatomic definition of the ostium and proximal epicardial course of coronary arteries [1, 2]. This report describes a case of TOF with an atrioventricular canal defect whose preoperative echocardiography showed abnormal origin of the left anterior descending artery (LAD) from right aortic sinus, which was interpreted as crossing the right ventricular outflow tract. Perioperative inspection did not show any abnormal vessel crossing the outflow, and corrective surgery was performed. At the echocardiographic evaluation after surgery, it was noted that the abnormal LAD arising from right aortic sinus was taking a septal course in relation to the posterior aspect of the pulmonary annulus. It is important to recognize this anomalous course because it is benign with no surgical implications.