December 1st 2003
Sudden Death Risk Tracked in Large, Long-Running Study of Young Athletes
Prospective study lasting more than two decades underscores need for preparticipation screening.
(BETHESDA, MD)—A cohort study that followed millions of young Italians over a 21-year period indicates that competitive sports can trigger sudden death from underlying cardiac problems among young athletes at more than twice the rate among non-athletes, according to the Dec. 3, 2003 issue of the Journal of the American College of Cardiology.
“The prevalence of sudden death in athletes was two-and-a-half times that in non-athletes. Sport activity increases the risk of sudden death because effort facilitates cardiac arrest in people bearing hidden cardiac defects. Therefore, identification of concealed diseases should be mandatory in order to rule out affected patients from sport eligibility,” said Gaetano Thiene, MD from the University of Padua in Padua, Italy.
The researchers took advantage of a system of standard preparticipation screening that has been in place in Italy for several decades. In addition, since 1979, clinical and pathological investigations of sudden death in people age 35 or younger have been standard in the Veneto Region in northeastern Italy. During the study period from 1979 through 1999, a total of 21 years, the population that was age 12 to 35 averaged more than 1.3 million. The population of young athletes averaged almost 113,000.
The study included 300 cases of sudden death, including 55 deaths of athletes. The rates of sudden death were 2.3 per 100,000 athletes per year and 0.9 per 100,000 non-athletes per year. Among the athletes who died, males outnumbered females 10 to one. The most common types of heart defects linked to sudden death in athletes were arrhythmogenic right ventricular cardiomyopathy (ARVC, which is an electrical disturbance of the heart) and coronary artery disease.
Dr. Thiene said the study demonstrated the importance and value of the Italian system of screening young athletes.
“Preparticipation screening is regulated by a law in Italy, which proved to be quite effective in reducing the risk of sudden death in athletes. I hope that also in the United States similar legislation will be introduced, in order to require preparticipation screening, including electrocardiograms and ultrasound,” Dr. Thiene said.
In an editorial in the journal, Roberta G. Williams, MD, FACC and Alex Y. Chen, MD, MSHS from the University of Southern California and Childrens Hospital Los Angeles in Los Angeles wrote that this study did a better job than previous research of sorting out the confounding effects of male to female ratio among athletes and non-athletes. The editorial authors also noted other key strengths of this effort: the universal preparticipation screening in Italy and the fact that all the pathologic studies were performed in a single program with “impeccable technique.” They noted, however, that differences in regulations, ethnicity and the common types of heart abnormalities may limit the applicability of the findings in the United States.
“We as cardiologists should press on with exploration of more reliable and affordable methods of detecting individuals at risk for sudden death during sports activities. This is a daunting task, considering the wide variability in expertise in diagnosing rare cardiac lesions and the immense economic pressure placed on and by the sports industry in this country. Nevertheless, this study illustrates that sensitive recognition of cardiac abnormalities by preparticipation screening, if followed by exclusion from competitive sports, will reduce mortality from sudden death,” Drs. Williams and Chen wrote.
Renu Virmani, MD, FACC from the Armed Forces Institute of Pathology in Washington, D.C., who was not part of this research team, said there is more than one possible explanation for the higher rate of ARVC observed in the Italian athletes.
“This difference between the U.S. and Italy may be due to regional and ethnic differences, or there may be differences in our definition of ARVC, or ARVC is being missed in the U.S. I think it is less likely to be an issue of ethnic differences. My personal experience is that investigators define ARVC very liberally and that strict definitions of ARVC including fibrosis and fat infiltration must be applied, or we are likely to be over-diagnosing ARVC, while other causes, such as prolonged QT syndrome and Burgada syndrome, may be missed,” Dr. Virmani said.
The American College of Cardiology, a 29,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.
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