Return to Play for Athletes After COVID-19 Infection: The Fog Begins to Clear.

Abstract

In October 2020, Kim and colleagues, representing the American College of Cardiology’s Sports and Exercise Council, published recommendations1 for the evaluation of athletes who had tested positive for COVID-19 to ensure safe return to play. The group recommended a tiered approach based on the presence of symptoms, followed by electrocardiography (ECG), injury biomarkers, and echocardiography. Abnormalities were then to be further characterized by the selective use of cardiac magnetic resonance (CMR) imaging. The recommendations were based on expert opinion of experienced sports cardiologists, because there were at the time only modest data to inform such a document. A report2 on 26 college athletes who were asymptomatic or had only mild symptoms found CMR evidence of myocarditis in 4 (15%). Both the Kim et al report1 and our Editorial3 at the time called for larger data sets, so that recommendations could be refined and more informed by data. In only 6 months since then, there has been a remarkable amount of information acquired, analyzed, and published regarding post–COVID-19 prevalence of cardiac abnormalities in athletes, as summarized in the Table.2,4-11 In a recent study of 789 professional athletes, screening consisted of serum troponin testing, ECG, and echocardiography, regardless of symptoms.8 Thirty of these athletes (3.8%) had abnormal test results resulting in referral for CMR imaging, with 3 diagnosed with myocarditis. Similarly, in a large cohort of 3018 college athletes from 42 universities,9 a strategy using serum troponin tests, ECG, and echocardiography identified 15 athletes (0.5%) with possible cardiac involvement. In a subgroup of 198 athletes in that report9 who underwent a primary CMR imaging–based screening strategy (ie, without selection by the other tests), a higher proportion of athletes demonstrated definite, probable, or possible cardiac involvement (n = 6 [3.0%]). In the current issue of JAMA Cardiology, a study by Daniels et al11 adds substantially to the extant information. As they note, starting in September 2020, the Big Ten athletic conference (involving 13 major universities) mandated comprehensive cardiac screening, including ECG, troponin testing, echocardiography, and CMR imaging for athletes in the aftermath of positive COVID-19 test results, regardless of prior symptomatic status. The authors report on a large sample of 2461 athletes, of whom 1597 (64.9%) had the complete comprehensive screening testing, including CMR imaging without prior selection. They found that 37 (2.3%) of these athletes demonstrated diagnostic criteria for myocarditis by CMR imaging, including 20 without cardiovascular symptoms and with normal ECG, echocardiography, and troponin test results, who would not have been identified without CMR imaging. While some of the prior studies involving smaller patient cohorts had also reported all athletes undergoing CMR imaging,2,4,5 it was unclear what selection may have taken place before CMR imaging referral. This mandated comprehensive testing in a large group of collegiate athletes provides the novel opportunity not previously available in large athlete cohorts (to our knowledge) to construct the data in their Figure 2,11 which succinctly summarizes what would have been detected and missed by various screening strategies. In the report by Moulson et al,9 among the 3018 athletes evaluated, almost 200 had screening that included CMR imaging without prior selection. The prevalence of cardiac abnormalities in that group was similar to that reported in the study by Daniels et al.11 Thus, the totality of data provides us with substantially more information to inform our thinking about screening and return to play than even just 6 months ago. We can be reasonably certain that the prevalence of signs on CMR imaging of myocarditis using the modified Lake Louise criteria is in the range of 1% to 3% in athletes following positive COVID-19 test results. Screening only on the basis of COVID-19 symptoms is insensitive. Sensitivity is improved by an algorithm combining the presence of symptoms as well as ECG, echocardiography, and troponin testing results. However, this approach will likely miss individuals who would be found to have CMR imaging evidence of myocarditis. While much has been learned, questions remain. First, what are the implications of finding evidence on CMR imaging of myocarditis in the absence of prior symptoms or abnormalities on cardiac testing? The findings from the studies illustrated in the Table and the study of Daniels et al11 demonstrate the increased diagnostic yield of CMR imaging for detecting COVID-19 cardiac involvement. There are limitations, in that independent core laboratory image interpretations were not performed based on practicality and funding and few studies had control referents.4,7 Moreover, the clinical significance of abnormalities of CMR imaging in young athletes in competitive sports remains unknown, as does the prevalence of such abnormalities in larger and more general cohorts of young athletes.12 Additionally, it is unclear if abnormalities on CMR imaging after COVID-19 represent markers for increased risk of sudden death in athletes, supporting an indication to restrict activity, because myocarditis in athletes has historically been diagnosed in the setting of cardiovascular symptoms and not by screening individuals without symptoms with CMR imaging. On the other hand, the absence of symptoms in athletes with myocarditis is not necesRelated article Opinion