Case report: mRNA COVID-19 vaccine-related acute pericarditis with evolution to myopericarditis.

This patient's clinical course was uncomplicated, which is consistent with studies indicating that post-COVID vaccine myocarditis usually has a mild course with a low chance of arrhythmia or heart failure. Troponin elevation is a part of the diagnostic criteria for myocarditis. This case is consistent with another report demonstrating that troponin levels can be within the normal range early in the clinical course of post-COVID vaccine myopericarditis. The incomplete right bundle branch block resolved by day 4 post-vaccination and thus may have represented early myocardial involvement at presentation. Further testing and monitoring should be considered in patients who present soon after COVID-19 mRNA vaccination with pericarditis features or minor conduction delays, in order to rule out progression to myopericarditis. Identifying myocardial involvement is clinically relevant as it indicates a risk of developing arrhythmia or heart failure, as well as having implications for physical activity advice and future booster vaccination.