Comparison of Multisystem Inflammatory Syndrome in Children-Related Myocarditis, Classic Viral Myocarditis, and COVID-19 Vaccine-Related Myocarditis in Children

• Type of Material: Article
• Authors: Trisha Patel, Emory University; Michael Kelleman, Emory University; Zachary West, Emory University; Andrew Peter, Emory University; Matthew Dove, Emory University; Arene Butto, Emory University; Matthew Oster, Emory University
• Language: English
• Date: 2022-05-03
• Publisher: WILEY
• Publication Version: Final Published Version
• Copyright Statement: © 2022 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.
• License: Creative Commons Attribution-NonCommercial 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1161/JAHA.121.024393
• Title of Journal or Parent Work: JOURNAL OF THE AMERICAN HEART ASSOCIATION
• Volume: 11
• Issue: 9
• Start Page: e024393
• End Page: e024393
• Grant/Funding Information: None
• Keywords: Science & Technology; Cardiac & Cardiovascular Systems; Cardiovascular System & Cardiology; myocarditis; mRNA vaccine; COVID-19; MIS-C; Life Sciences & Biomedicine; OUTCOMES
• Research Categories: Health Sciences, Medicine and Surgery

Abstract

BACKGROUND: Although rare, classic viral myocarditis in the pediatric population is a disease that carries significant morbidity and mortality. Since 2020, myocarditis has been a common component of multisystem inflammatory syndrome in children (MIS-C) following SARS-CoV-2 infection. In 2021, myocarditis related to mRNA COVID-19 vaccines was recognized as a rare adverse event. This study aims to compare classic, MIS-C, and COVID-19 vaccine-related myocarditis with regard to clinical presentation, course, and outcomes. METHODS AND RESULTS: In this retrospective cohort study, we compared patients aged <21 years hospitalized at our institution with classic viral myocarditis from 2015 to 2019, MIS-C myocarditis from March 2020 to February 2021, and vaccine-related myocarditis from May 2021 to June 2021. Of 201 total participants, 43 patients had classic myocarditis, 149 had MIS-C myocarditis, and 9 had vaccine-related myocarditis. At presentation, ejection fraction was lowest for those with classic myo-carditis, with ejection fraction <55% present in 58% of patients. Nearly all patients with MIS-C myocarditis (n=139, 93%) and all patients with vaccine-related myocarditis (n=9, 100%) had normal left ventricular ejection fraction at the time of discharge compared with 70% (n=30) of the classic myocarditis group (P<0.001). At 3 months after discharge, of the 21 children dis-charged with depressed ejection fraction, none of the 10 children with MIS-C myocarditis had residual dysfunction compared with 3 of the 11 (27%) patients in the classic myocarditis group. CONCLUSIONS: Compared with classic myocarditis, those with MIS-C myocarditis had better clinical outcomes, including rapid recovery of cardiac function. Patients with vaccine-related myocarditis had prompt resolution of symptoms and improvement of cardiac function.