I have performed many routine sports physicals in healthy kids who I encouraged to stay active and healthy. Every time I signed the “cleared for sports participation” line, I paused and thought about the limitations of screening tools for identifying risk factors for sudden cardiac death (SCD), a rare but devastating complication of a subset of cardiac conditions. One job of the primary care pediatrician is to find that high-risk needle in the haystack in healthy, resilient kids. Assessing risk of SCD, knowing the incidence of these “needles,” and understanding the limitations of screening tools are challenges for primary care physicians and outpatient cardiologists.
In a retrospective study published in this week’s NEJM, investigators from the Cardiology Clinical Academic Group at the St. George’s Hospital Medical School evaluated the effectiveness of cardiac screening and the incidence of SCD in in a cohort of screened, high-performing adolescent soccer players in the United Kingdom.
Malhotra et al. analyzed data from 11,168 screened soccer players (age range, 15–17, mostly male) in the English Football Association (FA) registry from 1996 through 2016. The FA has the largest mandatory cardiac screening program for adolescent athletes in the United Kingdom since 1996.
The mandatory cardiac screening program required each athlete to undergo a health questionnaire, physical exam, and a 12-lead electrocardiography (ECG) and echocardiogram. Athletes with concerning findings on initial screening underwent further testing, including exercise stress testing, 24-hour Holter monitoring, and cardiac magnetic resonance imaging. Deaths among athletes were determined from reports to the FA, surveys sent to health professionals at affiliated soccer clubs, and regular internet searches. Death certificates were obtained to help determine cause of death.
During the 20-year period, 42 athletes (0.38%) were found to have significant cardiac diseases associated with SCD. Most (26) of these athletes were diagnosed with a Wolff-Parkinson-White ECG pattern. Five athletes were diagnosed with hypertrophic cardiomyopathy, one with dilated cardiomyopathy, two with arrhythmogenic right ventricular cardiomyopathy (ARVC), three with long-QT syndrome (LQTS), and five with other disorders.
Most (86%) cardiac conditions associated with SCD were detected with ECG, followed by echocardiogram (29%), history (7%), and physical exam (5%). Most cardiac disease associated with SCD was electrical cardiac disease without any associated structural pathology. During a mean follow-up of 10 years, 23 screened athletes died. Eight deaths resulted from cardiac disorders, with a mean time from screening to death of 7 years. Of these 8 deaths, 6 were in athletes who had normal screening at age 16 and 7 deaths were associated with cardiomyopathies. Five of the 8 deaths occurred more than 5 years after screening.
The incidence of SCD in this cohort was nearly 7 per 100,000 athletes. This incidence is higher than previous estimates among athletes with minimal or no cardiac screening. Hypertrophic cardiomyopathy was the most commonly detected cardiomyopathy, with all affected athletes demonstrating an abnormal ECG and echocardiogram. Prevalence of hypertrophic cardiomyopathy was 1 in 1861, and lower than the prevalence reported in the general population.
The Take Away
In this population of mostly male adolescent athletes in the United Kingdom, the incidence of SCD was higher than previously reported. Most clinically apparent cardiac disease associated with SCD was electrical cardiac disease and detected by screening ECG. Most athletes who died from SCD died in adulthood and had no abnormalities on screening ECG or echocardiograms at age 16. These findings suggest that the athletes with SCD developed clinically significant cardiac disease in the interim.
This study suggests that the incidence of SCD among high-performing athletes is higher than previously thought. Although the results may not necessarily apply to the average teen athlete undergoing a routine preparticipation sports physical, the findings provide some insight into the potential benefits of cardiac screening in young athletes.
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Angela Castellanos is a general pediatrician and editorial fellow at the NEJM.