Clinically Suspected Myocarditis in the Course of Severe Acute Respiratory Syndrome Novel Coronavirus-2 Infection: Fact or Fiction?

Cardiac complications, including clinically suspected myocarditis, have been described in novel coronavirus disease 2019. Here, we review current data on suspected myocarditis in the course of severe acute respiratory syndrome novel coronavirus-2 (SARS-CoV-2) infection. Hypothetical mechanisms to explain the pathogenesis of troponin release in patients with novel coronavirus disease 2019 include direct virus-induced myocardial injury (ie, viral myocarditis), systemic hyperinflammatory response (ie, cytokine storm), hypoxemia, downregulation of angiotensin-converting enzyme 2, systemic virus-induced endothelialitis, and type 1 and type 2 myocardial infarction. To date, despite the fact that millions of SARS-CoV-2 infections have been diagnosed worldwide, there is no definitive proof that SARS-CoV-2 is a novel cardiotropic virus causing direct cardiomyocyte damage. Diagnosis of viral myocarditis should be based on the molecular assessment of endomyocardial biopsy or autopsy by polymerase chain reaction or in-situ hybridization. Blood, sputum, or nasal and throat swab virology testing are insufficient and do not correlate with the myocardial involvement of a given pathogen. Data from endomyocardial biopsies and autopsies in clinically suspected SARS-CoV-2 myocarditis are scarce. Overall, current clinical epidemiologic data do not support the hypothesis that viral myocarditis is caused by SARS-CoV-2, or that it is common. More endomyocardial biopsy and autopsy data are also needed for a better understanding of pathogenesis of clinically suspected myocarditis in the course of SARS-CoV-2 infection, which may include virus-negative immune-mediated or already established subclinical autoimmune forms, triggered or accelerated by the hyperinflammatory state of severe novel coronavirus disease 2019.