OBJECTIVES: The purpose of this study is to characterize the clinical profile and identify clinical markers that would enable the detection during life of anomalous coronary artery origin from the wrong aortic sinus (with course between the aorta and pulmonary trunk) in young competitive athletes. BACKGROUND: Congenital coronary artery anomalies are not uncommonly associated with sudden death in young athletes, the catastrophic event probably provoked by myocardial ischemia. Such coronary anomalies are rarely identified during life, often because of insufficient clinical suspicion. However, since anomalous coronary artery origin is amenable to surgical treatment, timely clinical identification is crucial. METHODS: Because of the paucity of available data characterizing the clinical profile of wrong sinus coronary artery malformations, we reviewed two large registries comprised of young competitive athletes who died suddenly, assembled consecutively in the U.S. and Italy. RESULTS: We reported 27 sudden deaths in young athletes, identified solely at autopsy and due to either left main coronary artery from the right aortic sinus (n = 23) or right coronary artery from the left sinus (n = 4). Each athlete died either during (n = 25) or immediately after (n = 2) intense exertion on the athletic field. Fifteen athletes (55%) had no clinical cardiovascular manifestations or testing during life. However, in the remaining 12 athletes (45%) aged 16 +/- 7, certain clinical data were available. Premonitory symptoms had occurred in 10, including syncope in four (exertional in three and recurrent in two, 3 to 24 months before death) and chest pain in five (exertional in three, all single episodes,