This may be due either to anatomic features that make anomalous aortic origin of the left coronary artery prone to coronary compromise or because a larger proportion of myocardium is supplied by the left coronary artery, or both. Exercise Autopsy series suggest a most patients die during, or in close temporal association with, exercise.S4.4.7-3 S4.4.7-5 Ischemia Autopsy series demonstrate myocardial fibrosis in a significant number of patients whose deaths were attributed to AAOCA, particularly in patients with anomalous left coronary artery arising from the right cusp.S4.4.7-5 Surgical series describe patients with ischemia or MI before surgical repair in the absence of other CAD, suggesting a relation of the coronary anomaly to the ischemia.S4.4.7-16 This suggests that had perfusion imaging been obtained before SCD, ischemia would have been found in such patients.S4.4.7-17,S4.4.7-18 However, other data indicate that a normal stress test does not preclude a SCD event, with the proviso that most of those studies used only stress ECG, rather than the more sensitive and specific modalities of nuclear perfusion imaging or stress echocardiography. In addition, postoperative studies have shown that ischemia may be found after surgical repair in the distribution not supplied by the abnormal coronary artery and may not persist on repeat Symptoms In autopsy and surgical series, a significant number of patients reported cardiovascular symptoms, including before SCD events.S4.4.7-4,S4.4.7-7,S4.4.7-8,S4.4.7-20,S4.4.7-21 Symptoms are more commonly reported in patients in whom the left coronary artery arises from the right sinus. Surgical series have described improvement in symptoms after surgical AAOCA indicates anomalous aortic origin of the coronary artery; CAD, coronary artery disease; ECG, electrocardiogram; MI, myocardial infarction; and SCD, sudden cardiac death. CLINICAL STATEMENTS AND GUIDELINES being wrong for a young patient with AAOCA may be perceived to be greater than for many other con- ditions. 