The central purpose of preparticipation screening of trained competitive athletes is to identify or raise suspicion of those cardiovascular abnormalities and diseases that are potentially responsible for sudden unexpected death on the athletic field.40,41,42,43,44,45,46,47,48,49 When such athletes are recognized, they are exposed to eligibility and disqualification decisions that become the responsibility of the practicing physician and are a subject of this document.39,40,41,42,43,44,45,46,47,48,49 There is general (although not universal) agreement with the principle that screening to detect important diseases and potentially prevent sudden death is justified and potentially beneficial.13,38,39,40,41,42,43,44,45,46,47,48
Currently, broad-based cardiovascular screening is practiced systematically in athletes at all levels of performance (not confined to the elite) in only three countries: in the United States with personal or family history and physical examination (but without ECGs) and in both Italy and Israel with 12-lead ECGs in addition to history and physical examination.38,39,40,41,42,43,44,45,46,47,48 In many European countries, screening of athletes is limited to those performing at the elite level (eg, in international, Olympic, or professional sports), and there is little information on nonathlete students.39,40,41,42 The potential benefit of such initiatives is identification of a small number of individuals with potentially lethal genetic and/or congenital cardiovascular diseases (eg, HCM) so that (1) they may be withdrawn from competitive sports to decrease their personal risk and generally make the athletic field a safer environment; and (2) in the process, some high-risk individuals will be identified who may be candidates for disease-modifying medical or surgical intervention or for prevention of sudden death with implantable defibrillators.
Italian investigators have intensely promoted screening with routine 12-lead ECGs (as well as history and physical) based on a unique > 30-year program mandated by Italian law and supported by sports medicine physicians dedicated full time to the program.40,41,42,43,44,45,46,47,48,49 Since 1997, Israel has maintained a similar mandatory ECG-based initiative and national sports law.50 For > 50 years, it has been customary practice in the United States to routinely screen high school– and college-aged athletes with history and physical examination (but without noninvasive testing).39,44,45,46,51,52,53,54,55,56,57 In contrast, Denmark has pointedly rejected systematic screening for cardiovascular disease in both athletes and any other segment of the population as unjustified in consideration of the low event rate.52 Other than Japan, no country has systematically attempted broad-based cardiovascular screening in general healthy populations (not limited to athletes), with or without ECGs.58,59
Universal Screening: Electrocardiogram Versus History and Physical Examination
Preparticipation screening for cardiovascular disease with personal or family history and physical examination has been the customary practice for all high school– and college-aged competitive athletes in the United States for decades, independent of their performance level. This process is guided by the 14-point history and physical examination elements proposed by the AHA.39,44,45,46 The AHA recommendations acknowledge that athletes and others with underlying (but undiagnosed) cardiovascular abnormalities may well manifest clinical warning signs (eg, chest pain, excessive exertional dyspnea, syncope) identifiable by careful and systematic history. Because most diseases responsible for sudden death in the young are genetic or familial, a thorough family history is likely to raise suspicion of the disorder. An organic heart murmur can alert the examining physician to valvular or other abnormalities, including LV outflow tract obstruction.
A controversy persists as to whether an ECG (in addition to history and physical examination) is superior to history and physical examination alone for detecting potentially lethal cardiovascular disease, particularly when taking into account the important issues of false-negative and false-positive results, as well as cost and resource availability.53 Indeed, studies comparing these two strategies have failed to demonstrate a mortality benefit for ECG screening.49
The debate between those strongly promoting routine ECGs and those opposed to ECGs as a routine screening tool is not fully resolved as yet, although a substantial literature consisting largely of editorials and viewpoint commentaries is accumulating rapidly. Nevertheless, several points are indisputable. First, the 12-lead ECG, while a mainstay of hospital-based cardiovascular practice for decades, is an unproven diagnostic tool for reliable detection of cardiovascular disease in generally healthy populations.59,60,61 Second, outcome data on athlete screening and mortality have been primarily driven by only one database, that of the Veneto region of Italy (9% of the national population) as part of their long-term screening program.49,51 This ambitious Italian initiative has been shown to be successful in identifying some at-risk athletes with potentially lethal cardiovascular disease (primarily right ventricular cardiomyopathy, which appears to be endemic in this area of Italy), resulting in mandatory withdrawal from sports.42 A sharp decrease in mortality over a 30-year period was demonstrated, which these investigators attributed to incorporation of the 12-lead ECG into the screening program in the early 1980s.43,44
Third, the Italian data showing that ECG screening reduces mortality in athletes have yet to be replicated elsewhere, and evidence from the United States and Israel appears to dispute and/or diminish the value of the ECG in reducing athlete mortality.50,53 For example, contemporary death rates in US athletes from Minnesota, where screening is limited to history and physical examination, do not differ from those in the Veneto region of Italy where the ECG is routinely employed, and athlete death rates from Israel did not differ before and after legislation for mandatory ECGs.50,53 The fact that it has been difficult to consistently show a reduction in athlete mortality directly attributable to routine ECGs is an observation that may be in part driven by the generally low event rates in competitive athletes with cardiovascular disease.50,53
Relevance of Sudden Death Incidence to Screening
Indeed, the low frequency with which sudden deaths occur in the competitive athlete population negatively impacts the justification for broad-based screening in large populations of young people, as well as the weight that can be afforded to this issue as a public health problem. In this regard, there is now overwhelming evidence that these events are relatively uncommon, albeit exceedingly tragic in each case. Most data place these cardiovascular sudden deaths in the range of about 1 per 80,000 to 1 per 200,000 participants per year, much less common in relative terms than motor vehicle accidents (5000-fold), suicide, drugs, homicide, or cancer in the same age group, and similar in frequency to that of fatal lightning strikes.44,62,63 In a college (National Collegiate Athletic Association [NCAA]) athlete population, drugs and suicide combined accounted for a similar number of deaths as did confirmed cardiac disease, although a non–forensic-based analysis reported a higher incidence for sudden death.64
Furthermore, the absolute number of sudden deaths as a result of documented cardiovascular disease in competitive athletes is small in populations for which forensic data are reported. For example, the 33-year US Sudden Death in Athletes Registry has reported a maximum of 75 such deaths in any given year nationally, and the Veneto database has reported 55 sudden deaths in 26 years, or only about two deaths per year.44 In other populations, the average number of confirmed cardiovascular deaths annually is much less (ie, less than one death in Minnesota high school athletes or about four deaths in college [NCAA] athletes).36,46 Notably, of major concern are false-negative screening results in which the system fails to identify cardiac disease that is in fact established. Indeed, a substantial proportion of athletes (about 30%-40%) may die suddenly of cardiovascular abnormalities that would not necessarily be reliably detected by screening, even with ECGs.64
Universal Electrocardiogram Screening
On multiple occasions, AHA consensus expert panels have evaluated and decided not to support mandatory national athlete screening in the United States with routine use of ECGs.43,44,45,46 Indeed, sudden cardiovascular deaths in athletes are rare (albeit tragic) events insufficient in number to be judged as a major public health problem or justify a change in national health care policy. The most frequently cited obstacles to mandatory national screening of trained athletes are as follows: (1) the large number of athletes to be screened nationally on an annual basis (ie, about 10-12 million); (2) low incidence of events; (3) substantial number of expected false-negative and false-positive results in the wide range of 5% to 20% depending on the specific ECG criteria used; (4) cost-effectiveness considerations (ie, extensive resources and expenses required vs few events in absolute numbers); (5) liability issues unavoidably impacting physicians (ie, charged with both enforcement and the sole responsibility to disqualify athletes from competition); (6) lack of resources or physicians dedicated to performing examinations and interpreting ECGs, in contrast to the long-standing sports medicine program in Italy; (7) influence of observer variability, technical considerations, and the impact of ethnicity/race on the interpretation of ECGs, particularly important for multicultural athlete populations such as in the United States; (8) need for repetitive (ie, annual) ECG screening during adolescence, given the possibility of developing phenotypic evidence of cardiomyopathies during this time period or later; (9) logistical challenges and cost related to second-tier confirmatory screening with imaging and other testing, should primary evaluations raise the suspicion of cardiac disease; and (10) recognition that even with testing, screening cannot be expected to identify all athletes with important cardiovascular abnormalities and that a significant false-negative rate can be expected.39,40,41,42,43,44,45,46,47,48,49,65,66,67,68,69
Nonuniversal Screening for Athletes
Screening programs on a smaller regional and non-national basis have been implemented in some high schools, colleges, and local communities using ECGs (or echocardiograms) with varying expertise, quality control, and results for identifying important cardiac disease. Consistently, the AHA has not opposed ECG-based screening initiatives (often performed by volunteers) in smaller venues. However, for such screening initiatives, the AHA has prudently advised adequate quality control with due consideration for the prominent limitations of the process (including false-negative and false-positive test results) so that the risks as well as benefits can be understood and are acceptable to all participants, communities, and organizations.44,45,46 Sudden deaths caused by genetic or congenital heart disease are more common in nonathletes than athletes. This brings to the forefront an ethical issue regarding systematic screening of athletes exclusively.
There are certain known and anticipated limitations in using ECGs in population screening, including (but not limited to) false-positive and false-negative test results, technical and interpretation issues, “gray zone” ambiguous diagnoses, and cost and logistics involved in arranging second-tier diagnostic testing, all of which promote anxiety, uncertainty, and legal considerations.44,45