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Sudden Death in Athletes
Abstract & Commentary
By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco is a consultant for Novartis and does research for Medtronic and Guidant.
Source: Maron BJ, et al. Sudden deaths in young competitive athletes: Analysis of 1866 deaths in the United States, 1980-2006. Circulation. 2009;119:1085-1092.
The U.S. National Registry of Sudden Death in Athletes assembles and analyzes data on the deaths of young athletes who participate in competitive sports. The Registry systematically collects reports of death in athletes using a number of different search techniques, including informational databases, news media accounts, internet search engines, and voluntarily submitted reports. In the Registry, an athlete is defined as "someone who participates in an organized team or individual sport that required regular competition against others as a central component, placed a high premium on excellence and achievement, and required systematic and, in most instances, vigorous training." Deaths related to participation in intramural sports or informal recreational activities are not included.
During a 27-year period, the Registry collected data on 1,781 athletes who died suddenly and 85 athletes who survived an episode of cardiac arrest. The absolute number of reports has increased over time at a rate of about 6% per year, with a higher proportion of female athletes also noted over time. There were 513 deaths that could not be classified due to incomplete information.
In the entire group of 1,866 sudden deaths or cardiac arrests, a probable or definite cardiovascular cause was identified in 1,049 (56%). Hypertrophic cardiomyopathy was the most common abnormality identified, occurring in 251 of the 1,049 cases. In order of frequency, the next most common cardiovascular conditions identified were: coronary artery anomalies (119 cases), myocarditis (41 cases), arrhythmogenic right ventricular cardiomyopathy (30 cases), and long QT syndrome (23 cases). In 75 of these athletes, the cardiac disorder had been diagnosed during their lifetime but they had continued to participate in organized competitive sports. In six, this was despite restriction recommended by their physician. The mean age at the time of death was 18 ± 5 years, with 65% of the events occurring in those ≤ age 17, 29% between 18 and 25, and 7% between age 26 and 39. Hypertrophic cardiomyopathy and congenital coronary anomalies were more common causes of death among non-Whites than among Whites. Ion channelopathies were more common among Whites. After cardiovascular disorders, trauma was the next most common cause of sudden death. There were 416 deaths that resulted directly from blunt trauma, most frequently with injuries to the head and neck. Blunt injury as a cause of sudden death during sports was most frequently seen during motor sports (97), football (140), skiing (15), boxing (42), track and field (25), and equestrian competition (24). There were 65 cases of commotio cordis, with sudden death or cardiac arrest occurring immediately after a blunt precordial blow. Additional nontraumatic, non-cardiac causes of death included heat stroke (46), drug use (34), asthma (15), and pulmonary embolism (13). Sudden cardiovascular death events occurred most commonly during or just after physical activity. However, 20% of the sudden deaths among trained athletes occurred under circumstances not immediately associated with sports activity. Using an estimate of 10.7 million sports participants, the incidence of sudden death was 0.61 per 100,000 person years.
Maron et al concluded that sudden death in U.S. competitive athletes is a low-frequency event. Cardiovascular disease and blunt trauma are the most commonly identified causes. The low frequency of events among participants makes design of effective screening programs to reduce sudden death during athletics difficult.
Sudden death during athletic competition is a fortunately infrequent, but very high-profile topic. The death of an athlete stirs the public interest and arouses emotions about a young life needlessly lost. These data from a long-running national registry highlight some of the problems involved in combating this problem. In Europe, the approach has been to mandate pre-participation screening of all athletes with history, physical exam, and ECG. In the United States, the current recommendations are more conservative in that they do not include routine ECG recordings. This is due to the costs and difficulty involved in obtaining ECGs in the millions of athletes below the college level and of doing follow-up tests if abnormalities are detected. The issue of positive ECG findings that are not clinically significant is highlighted by reports that up to 30%-40% of elite college athletes may have some abnormal ECG finding in the absence of any cardiac condition that should restrict activity. We have a similar experience here at the University of Virginia where all varsity athletes are screened as part of an ongoing research program.