Daniel Montellese, MD
The first documented case of sudden cardiac death occurred in 490 BC, when Pheidippides, a Greek soldier who ran from Marathon to Athens to spread the news of his army’s victory over Persia, delivered his message and then collapsed and died. In the modern era, the sudden death of a number of high-profile athletes has raised public interest in this infrequent event. The public perceives young competitive athletes as robust invulnerable members of our society. Their unexpected death often incites heated debate among the public and, more specifically, the medical community on the prevention of sudden cardiac death and the appropriateness of the existing screening guidelines.
The largest available studies estimate the risk of sudden cardiac death among high school and collegiate athletes to be between 1 per 100 000 and 1 per 300 000 each year.1-3 An estimated 50 to 100 cases occur in the United States annually.3,4 Being symptomatic prior to a sudden cardiac death event is more often the exception rather than the rule. These devastating events are frequently the presenting clinical manifestation of an underlying cardiovascular disorder. One of the earliest clinicopathologic studies in young competitive athletes identified structural cardiovascular abnormalities in 28 of 29 athletes, with hypertrophic cardiomyopathy as the most likely etiology of sudden death in 14 of the 29 cases.3 In 1991, a review of prior studies found that the most common etiology of sudden cardiac death in athletes was hypertrophic cardiomyopathy, occurring 24% of the time, followed by coronary anomalies (18%) and myocarditis (12%).5 The remaining cases of sudden cardiac death in athletes relate to other cardiac electrical disorders, such as long QT syndrome and Wolff-Parkinson-White syndrome, or commotio cordis (ventricular arrhythmia induced by blunt chest wall trauma in a structurally normal heart), as well as complications of asthma and substance misuse.4
The American Heart Association Science Advisory and Coordinating Committee developed consensus recommendations and preparticipation screening guidelines in 1996. The purpose of screening is to identify preexisting cardiovascular abnormalities that place athletes at increased risk for sudden cardiac death and to provide medical clearance by means of routine and systematic evaluations. The Committee recommended that a screening history and physical examination be performed on all athletes before participation in high school and collegiate sports. For high school athletes, the screening should be repeated every 2 years, and an interim history should be obtained in the intervening years. For college athletes, a history and blood pressure measurement should be obtained each year after the initial evaluation. The examination process does not currently include the use of electrocardiograms (ECGs) or echocardiography. The question of whether this approach is adequate remains.
In 2005, the European Society of Cardiology (ESC) issued a consensus statement recommending that every young competitive athlete undergo cardiovascular screening. As in the United States, the recommended protocol calls for a complete physical examination and personal and family medical history. However, the ESC also mandates a 12-lead ECG, which has not been required in the United States to date. These recommendations are largely based on Italy’s experience, which spans 25 years of mandatory systematic prescreening of athletes. The findings of a study published by Corrado and colleagues in 2005 indicated that the risk of dying of sudden cardiac death among young athletes was 2 1/2 times that of nonathletes.6 The lead author, Domenico Corrado, from the University of Padua, said he believed ECGs could screen as sensitively as echocardiograms, while producing a false-positive rate of about 10%.
Under ESC guidelines, the recommended cardiovascular evaluation should consist of complete personal and family history, physical examination with blood pressure measurement, and 12-lead ECG. The inclusion of a 12-lead ECG represents the additional value of this screening protocol and is based on the fact that the ECG offers the potential to detect, or to raise clinical suspicion of, potentially lethal conditions, including hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia, dilated cardiomyopathy, myocarditis, long QT syndrome, Brugada syndrome, Lenègre disease, catecholaminergic ventricular tachycardia, short QT syndrome, and Wolff-Parkinson-White syndrome. Based on published studies from the United States and Italy, these conditions, including hypertrophic cardiomyopathy, account for up to 60% of sudden deaths in young competitive athletes.7,8
The screening of US high school and college athletes, based on medical history and physical examination without ECG, does not adequately identify those cardiovascular abnormalities that increase the athlete’s risk of sudden cardiac death. In 1 retrospective study, only 3% of US-trained athletes who died suddenly of heart disease confirmed on autopsy had been suspected of having cardiovascular abnormalities on the basis of preparticipation screening, and none with hypertrophic cardiomyopathy were previously identified.7 By comparison, the European experience shows that screening is able to identify asymptomatic athletes with hypertrophic cardiomyopathy, and observation of these athletes during long-term follow-up suggests that withdrawal from competition has the potential to improve their survival.8 Analysis of the Italian data shows that fewer than 25% of young competitive athletes diagnosed with hypertrophic cardiomyopathy had an abnormal physical examination or positive family history. Thus, the majority of them would have not been identified by a screening protocol without 12-lead ECG.
The European experience has shown that a systematic preparticipation evaluation including 12-lead ECG can be a practical effective tool to identify patients with hypertrophic cardiomyopathy, the most common cause of sport-related sudden cardiac death. The American Heart Association current consensus panel states that “cardiovascular screening for young competitive athletes is justifiable and compelling on ethical, legal, and medical grounds.”9 The Italian experience suggests that adding ECG to the process used in the United States may improve the current system, which many feel is inadequate.
A dilemma, however, still remains. How do we implement an effective prescreening process that is realistically applicable in the United States, with its large population, ongoing emphasis on cutting health care costs, and an increasingly litigious atmosphere? The main criticism of the European protocol points toward the 9% false-positive rate (in the targeted population, to identify 1 patient, there would be 1999 false positives). The detractors contend that such a system would prevent “normal healthy” individuals from participating in athletics. Many will argue, however, that this is a small price to pay to prevent the untimely death of a young person in the prime of his or her life.
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