Screening of athletes
The question is not only whether or not screening should be undertaken, but also what this screening should include. Internationally, three strategies are being used. The simplest consists of a systematic mapping of family history and symptoms, combined with a clinical examination. This strategy is used especially in the United States by the National Football League (NFL), Major League Baseball (MLB) and the National Hockey League (NHL).
Furthermore, resting ECG can be added to the screening protocol. Recent data show that this significantly increases diagnostic accuracy (8). Without the addition of ECG, purely clinical protocols in screening studies have been able to detect only < 10 % of potentially life-threatening cardiovascular disease (9). Adding ECG is recommended by the IOC, FIS and ESC, among others. A key argument against ECG screening is that 2–3 % of the findings will be false-positives that will need further examination (10).
The third strategy also includes echocardiography and is recommended by FIFA and UEFA, among others. The Norwegian football league system is also subject to this, and all male players in the two top divisions are screened regularly. A simplified version of this strategy proposes echocardiography in adolescence to exclude structural heart disease and in the early thirties to assess changes induced by exercise, functional anomalies and late-onset cardiomyopathies (11).
A national screening programme should be constructed according to the same model and based on the experience gained from other national screening programmes
Because sudden cardiac arrest is so rare, it is not practicable to conduct randomised trials of the effect of systematic screening. However, a number of large observational studies have been undertaken both in the United States and in Europe (12). Perhaps the best-known study is from the Veneto region in Italy, which has screened athletes since 1982. The results have been promising, with a considerable decline in fatality rates. However, some weaknesses have been pointed out in its methodology (13).
In 2018, the results from 20 years of mandatory screening of 16-year-olds in the English football league system were published in the New England Journal of Medicine (14). Of 11 168 young footballers, eight died from sudden cardiac arrest. With an incidence of 6.8/100 000, the rate of sudden cardiac arrest was higher than might be expected among athletes, and higher than the rate of traffic fatalities among young people. Six of these eight had normal screening findings. The remaining two were among the 42 footballers who were disqualified because of screening findings, but nevertheless chose to continue with high-intensity exercise. The study can be read as a defence of screening, in that it prevented a considerable proportion of 40 disqualified athletes from succumbing to sudden cardiac arrest. However, it can also be given the opposite interpretation, in that despite massive resource use, it failed to achieve a lower incidence of sudden cardiac arrest than in non-screened populations.