In Reply We appreciate comments on our recent Viewpoint1 and the opportunity to respond to these important questions. Santos-Ferreira and colleagues recommend that coronavirus disease 2019 (COVID-19) return-to-play guidelines should emphasize symptoms and retesting. In terms of the controversy of retesting, recent data report recovered and noninfectious patients may shed detectable severe acute respiratory syndrome coronavirus 2 RNA for up to 3 months.2 Further, persons with mild to moderate COVID-19 infection do not appear to be infectious after 10 days following symptom onset; persons with more severe illness are likely not infectious after 20 days following symptom onset.2
We agree that burden of symptoms should dictate the degree of cardiac testing, which was included as part of our risk stratification algorithm.1 However, more expedient testing (including lung function tests) prior to the conclusion of quarantine introduces public health risks and should be ordered with caution. Current guidelines from the US Centers for Disease Control and Prevention, with which we concur, support these recommendations and advise a quarantine period for asymptomatic individuals with COVID-19 and those with mild symptoms.2 Importantly, symptoms may worsen during the second week of active infection, and a quarantine period of at least 10 days after symptom onset is still recommended by the Centers for Disease Control and Prevention.2 Santos-Ferreira and colleagues remind us that the pulmonary complications of COVID-19 manifest as pulmonary fibrosis, particularly in those with persistent exercise intolerance. Our approach would be to first prioritize public health measures. In combination with cardiac risk stratification, it would then be reasonable to consider lung function tests at the appropriate end of the quarantine period.
Greene and colleagues provide insightful comments regarding high-sensitivity cardiac troponin (hs-cTn) testing. They correctly point out that established reference ranges for athletes are lacking and that there should be consideration of the effect of prolonged strenuous exercise on release of hs-cTn. However, exercise-induced hs-cTn release typically returns to baseline within 24 to 48 hours, which differs from the kinetics of pathologic myocardial injury.3-5 We recommend a rest period of 48 hours prior to testing to avoid this potential confounder. We also appreciate concerns about hs-cTn as a gatekeeper for returning to play. However, the combination of electrocardiography, echocardiography, and hs-cTn should be sufficient to avoid false negatives. Risk of false positives also remains low as, in our experience, outside of the immediate postexercise period, it is rare for athletes to present with hs-cTn levels higher than the 99th percentile. We agree that sex-specific reference ranges for hs-cTn are important but might be assay dependent. We concur that serial hs-cTn should be interpreted using the same assay for clinically meaningful comparisons. While we strongly advocate for research to establish normal hs-cTn ranges in athletic populations and for interpretation of serial measures of hs-cTn, it is our opinion that these undertakings should not delay use of our algorithm and do not lessen the utility of hs-cTn in the current algorithm.
Finally, it is accurate that the most common screening test for COVID-19 is now polymerase chain reaction amplification of RNA vs antigen testing. This preference has evolved, and we would defer the selection of which test to local resource considerations.
Corresponding Author: Eugene H. Chung, MD, MSc, University of Michigan, Michigan Medicine, 1500 E Medical Center Dr, SPC 5856, Ann Arbor, MI 48109 (chungeug@med.umich.edu).
Published Online: November 4, 2020. doi:10.1001/jamacardio.2020.5351
Conflict of Interest Disclosures: Dr Kim is the team cardiologist for the National Football League Atlanta Falcons. No other disclosures were reported.