U.S, 29 June 2021, Kim et al, JAMA Cardiology
In this study of 7 patients with acute myocarditis, 4 occurred within 5 days of COVID-19 vaccination between February 1 and April 30, 2021. All 4 patients had received the second dose of a messenger RNA (mRNA) vaccine, presented with severe chest pain, had biomarker evidence of myocardial injury, were hospitalized, and had cardiac magnetic resonance imaging findings typical of myocarditis. All had regional wall motion abnormalities on cine imaging, and ejection fraction ranged between 40% and 59%. LGE was present in a nonischemic pattern consistent with myocarditis.