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

  1. Trisha Patel
  2. Michael Kelleman
  3. Zachary West
  4. Andrew Peter
  5. Matthew Dove
  6. Arene Butto
  7. Matthew E. Oster

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Abstract

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 myocarditis, 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 discharged 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.

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  3. Version published to 10.1161/jaha.121.024393
  4. ScreenIT

    SciScore for 10.1101/2021.10.05.21264581: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsIRB: The study was approved by the Institutional Review Board of Children’s Healthcare of Atlanta.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical Analysis: Statistical analyses were performed using SAS v9.4 (SAS Institute, Cary, NC) and statistical significance was assessed at the 0.05 level.
    SAS Institute
    suggested: (Statistical Analysis System, RRID:SCR_008567)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Limitations: There are important limitations in our study. Our data reflect patients hospitalized at a single tertiary pediatric institution. Thus, it represents our center’s approach to classic myocarditis, MIS-C myocarditis, and vaccine-related myocarditis and may not be generalizable to all children with myocarditis. By including only hospitalized patients, we also may have missed patients with subclinical findings, in whom the clinical course may have been different. Additionally, we did not have cardiac MRI data for comparisons between the groups. Given the concerns for active infection and potential hemodynamic instability, patients with MIS-C myocarditis did not undergo cardiac MRI at the time of presentation. Cardiac MRI (cMRI) is the gold standard for non-invasive diagnosis of myocarditis and thus, even in the setting of elevated troponin and symptoms, some patients with MIS-C myocarditis included in this study may not have met cMRI criteria for diagnosis of myocarditis. 5 The inclusion of patients with signs of mild myocardial inflammation but not true myocarditis based on cMRI may therefore have overrepresented the number of patients who had full cardiac recovery. The patients with vaccine-related myocarditis did undergo cardiac MRI during their initial hospitalization, but most have not yet undergone follow-up MRI testing. This testing will be important to assess for evidence of ongoing myocardial inflammation and risk for sequelae other than decreased function. F...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  5. Version published to 10.1101/2021.10.05.21264581v1 on medRxiv