Anomalous origin of the left main coronary artery from the right coronary artery with a preaortic course

We report the case of a 51-year-old woman who presented with stable angina pectoris and Canadian Cardiovascular Society class II functional capacity. An electrocardiogram during a treadmill exercise test showed substantial ST-segment depression in the inferolateral leads. Coronary angiograms revealed an anomalous origin of the left main coronary artery from the opposite sinus of Valsalva and an interarterial course between the ascending aorta and pulmonary artery. Although this phenomenon is dangerous, the patient refused further examination. We discuss the diagnosis and treatment of patients who have an anomalous origin of a coronary artery from the opposite sinus of Valsalva.