Myocarditis After SARS-CoV-2 Vaccination With mRNA Vaccines

Quick Takes

  • There appears to be a temporal correlation between SARS-CoV-2 vaccination with mRNA vaccines and mild myocarditis.
  • Additional study is required to prove causality and understand the mechanism for this issue.

Study Questions:

What are the characteristics of patients with myocarditis temporally correlated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination?

Methods:

A series of six patients is reported. Clinical presentation, electrocardiography (ECG), troponin values, and cardiac magnetic resonance imaging (CMR) findings are described.

Results:

Patients were males between 17–37 years old, with three in the 16–20 age group, two in the 21–25 age group, and one in the 35–40 age group. Time between vaccination and presentation ranged from 2–4 days. Common symptoms included positional and pleuritic chest discomfort as well as malaise. ECG abnormalities were common and included either ST elevation (five patients) or nonspecific ST-wave changes. Peak cardiac troponin I ranged from 5.21–38.3 ng/mL. Left ventricular ejection fraction ranged from 45–58% with five of six patients having abnormal left ventricular systolic function. CMR was consistent with the acute inflammation of myocarditis. No patients suffered additional complications and all were discharged home.

Conclusions:

The authors concluded that while the clinical presentation, CMR findings, and temporal association strongly suggest the possibility of vaccine-associated myocarditis in these six patients, one cannot conclude definitively that COVID-19 vaccine was causative or that other etiologies for myocarditis can be definitively excluded.

Perspective:

As more young patients have been vaccinated with mRNA vaccinates over the last several weeks and months, there have been increasing reports of myocarditis occurring several days after vaccination, particularly in young males after the second dose. On June 10, the CDC reported that across all ages, 789 cases of myocarditis/pericarditis had been reported, of which 475 had occurred in patients <30 years old. Case rates for 16- to 17-year-olds and 18- to 24-year-olds were 35 and 21 per one million doses, respectively: (https://www.aappublications.org/news/2021/06/10/covid-vaccine-myocarditis-rates-061021).

There appears to be a temporal correlation between vaccination with mRNA vaccination and myocarditis. This myocarditis appears to be generally mild. Further study is required to prove a causal relationship and better understand the mechanisms of this process. Clinicians should be aware of this potential issue and consider myocarditis in patients presenting with chest discomfort after vaccination.

Clinical Topics: Arrhythmias and Clinical EP, Congenital Heart Disease and Pediatric Cardiology, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Stable Ischemic Heart Disease, Vascular Medicine, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Imaging, CHD and Pediatrics and Prevention, Magnetic Resonance Imaging, Chronic Angina

Keywords: Adolescent, Arrhythmias, Cardiac, COVID-19, Diagnostic Imaging, Electrocardiography, Inflammation, Magnetic Resonance Imaging, Myocarditis, Pediatrics, RNA, Messenger, SARS-CoV-2, ST Elevation Myocardial Infarction, Stroke Volume, Troponin I, Vaccination, Ventricular Function, Left, Young Adult


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