Coronavirus-induced myocarditis: A meta-summary of cases

Myocarditis caused by SARS-CoV-2 infection was proposed to account for a proportion of cardiac injury in patients with COVID-19. However, reports of coronavirus-induced myocarditis were scarce. The aim of this review was to summarise the published cases of myocarditis and describe their presentations, diagnostic processes, clinical characteristics and outcomes.

A literature search of MEDLINE, EMBASE, Scopus, Web of Science, CENTRAL and OpenGrey on was performed on 3 June 2020. Studies of myocarditis in patients with COVID-19 were included, and those only reporting cardiac injury or heart failure were excluded. Cases were "confirmed" myocarditis if diagnosed on cardiac magnetic resonance imaging (CMR) or histopathology. Those without were grouped as "possible" myocarditis.

A total of 31 studies on 51 patients were included; 12 cases were confirmed myocarditis while 39 had possible myocarditis. The median age was 55 and 69% were male. The most common presenting symptoms were fever, shortness of breath, cough and chest pain. Electrocardiogram changes included non-specific ST-segment and T-wave changes and ventricular tachycardia. Most patients had elevated cardiac and inflammatory biomarkers. Left ventricular dysfunction and hypokinesis was common. CMR established the diagnosis in 10 patients, with features of cardiac oedema and cardiac injury. Five patients had histopathological examination. Some cases required mechanical ventilation and extracoporeal membrane oxygenation, and 30% of patients recovered but 27% died.

COVID-19 myocarditis was associated with ECG, cardiac biomarker and echocardiographic changes, and the manifestation could be severe leading to mortality. Endomyocardial biopsy was not available in most cases but CMR was valuable.