"Case report
A 27-year-old man was transferred to the emergency room in cardiopulmonary arrest. The patient had just received the first dose of the mRNA-1273 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (Moderna, Cambridge, MA, USA) 8 days earlier and had no symptoms such as chest pain suspected of myocarditis or general fatigue suspected of low cardiac output after the vaccination until the emergency room visit. He had a high exercise habit; his teammates called for an ambulance when he was found sitting unconscious during practice. Upon arrival at the emergency room, he presented asystole. Despite cardiopulmonary resuscitation, fatal ventricular arrhythmias repeated, and he eventually received venoarterial extracorporeal membrane oxygenation (VA-ECMO) and Impella CP (Abiomed, Danvers, MA, USA), after 2 h of his visit. A chest radiograph obtained in an emergency room showed an enlarged heart and pulmonary congestion...
We considered the patient to have fulminant myocarditis developed in the presence of stage B heart failure due to chronic severe MR [mitral regurgitation]... The patient died on day 28 due to progressive multiorgan failure...
Discussion
[T]he autopsy showed obvious severe myocardial inflammation findings, leading to the diagnosis of myocarditis... Microscopic findings showed infiltration of T cells, macrophages, and eosinophils. Such myocarditis with lymphocytic and eosinophilic infiltration has been reported after mRNA COVID-19 vaccination. Lymphocytic and eosinophilic infiltration was also observed in myocarditis after smallpox vaccination and a mechanism of immune-mediated myocarditis has been speculated. In addition, Frustaci et al. reported three cases of pathohistologically defined eosinophilic myocarditis after COVID19 vaccination, referring to the possibility of eosinophilic myocarditis (hypersensitivity myocarditis) as an allergic reaction and the possibility that immunosuppressive therapy including steroids may be effective."
© 2022 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).