COVID-19-Associated Acute Myocarditis: Risk Factors, Clinical Outcomes, and Implications for Early Detection and Management.

Background The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus causing acute respiratory distress with multisystem complications, including cardiac complications. Acute myocarditis is one possible complication of coronavirus disease 2019 (COVID-19). Previous studies revealed that mortality from COVID-19 was higher in patients with cardiac complications. Objectives We aim to identify if patients with COVID-19 develop myocarditis and if this condition is associated with an increased incidence of ventilatory support and mortality. We also aim to identify if preexisting cardiac conditions are associated with an increased incidence of ventilatory support and mortality in those who developed COVID-19. Methods This is a multicenter, retrospective study including patients aged 18 years and older. Statistical analysis was performed to compare the incidence of in-hospital mortality and ventilatory support in COVID-19-positive patients with and without myocarditis. In this study, we defined myocarditis using elevated troponin-T (TnT) and brain natriuretic peptide (BNP) levels as proxy. Results A total of 8,162 patients with a positive COVID-19 polymerase chain reaction (PCR) test were identified. Of those, 1,643 (20.1%) were found to have new-onset acute myocarditis. The risk of ventilation and mortality in these patients was significantly elevated (p<0.001) compared to patients without acute myocarditis. Underlying heart failure was associated with increased odds of in-hospital mortality, which was 1.6 times greater when compared to patients without heart failure. The odds of in-hospital mortality were 2.33 times as likely for those who had non-ischemic cardiomyopathy as opposed to those who did not. Conclusion Myocarditis is a serious and potentially fatal complication of COVID-19. The results of this study highlight the importance of routine testing of troponin-T and BNP levels to identify those at risk. Furthermore, underlying heart conditions are associated with a worse outcome, and those patients should be watched closely.