A nomalous origin of the left main coronary artery (LMCA) from the anterior (right) sinus of Valsalva, as well as other congenital coronary anomalies, have been incriminated as causes of sudden death in asymptomatic persons,‘” including competitive athletes.4 We previously reported that it is possible to identify such malformations prospectively, using conventional transthoracic echocardiography, and have suggested the possible role of echocardiography in the detection of anomalous origin of the LMCA in screening young athletes for cardiovascular disease.5 Therefore, the present investigation was undertaken to assess the efficacy of this diagnostic approach and the prevalence of such coronary anomalies in a surviving athletic population. Between January 1990 and August 1991, 1,360 athletes were evaluated consecutively at the Institute of Sports Science (Rome, Italy) and routinely subjected to an echocardiographic assessment that included examination of the ostia of the right and left coronary arteries, using cross-sectional views of the aorta from the parasternal and apical windows.6 In each of these athletes particular care was taken, in a prospective fashion, to achieve the optimal dejnition of the coronary ostia. Of the 1,360 athletes, 87 (6%) were excluded because of technically unsatisfactory echocardiograms, in which the origin of neither the left or the right coronary artery (RCA) could be imaged from d@erent acoustic windows. Thus, the @al study population comprised 1,273 athletes. All were asymptomatic and judged to be free of systemic or cardiovascular disease. Athletes were 13 to 49 years of age (mean 22); 828 were male (65%). Each was an elite athlete, having participated in vigorous training programs and competition for periods of 3 to 20 years. They were engaged in a wide range of 25 di$erent sports and about one third had achieved an international level of competition. In 1,257 of the 1,273 athletes (9X7%), the ostium of the LMCA was visualized with its origin in the normal position (at, or about, 5 o’clock in the short-axis view of the aortic root) (Figure 1). In only 16 athletes was the ostium of LMCA not visualized; however; in these 16, the RCA was identijied in its proper position and there was no evidence of the LMCA emanating from the right sinus of Valsalva. Therefore, in the 1,273 athletes studied, an anomalous origin or course of the LMCA could be excluded. In 225 of the 1,257 athletes in whom the LMCA was visualized, the course of the LMCA could be followed to its btjia-cation for 3 to 20 mm (average 11); in 87 of these 225 athletes the proximal portions of the left anterior descending and the left cir-