Dynamic change of an electrocardiogram in myocarditis following mRNA COVID-19 vaccination

ABSTRACT

Background and Aim: Coronavirus disease (COVID-19) is a pandemic infectious disease caused by the SARS-CoV-2 virus. At the begin-ning of 2021, the Food and Drug Administration (FDA) of the United States issued an emergency use authorization (EUA) for the Pfizer-BioNTech COVID-19 vaccine to prevent COVID-19 infection. Cases of myocarditis and pericarditis after the vaccination in adolescents and young adults have been reported, especially more often after the second dose. There are very few case reports in Asia. We aim to present a case of confirmed myocarditis after the Pfizer-BioNTech COVID-19 vaccine in Thailand and the remarkable dynamic change in an electrocardiogram (ECG). Method(s) Case report. We reported the case and reviewed serial electrocardiogram and echocardiographic findings, including car-diac magnetic resonance imaging (MRI) in a case of confirmed myocarditis after the Pfizer-BioNTech COVID-19 vaccine. Result(s) A previously healthy 13-year-old boy presented with chest pain and shortness of breath within 20 hours following the second dose of the Pfizer-BioNTech COVID-19 vaccine. Electrocardiogram (ECG) revealed diffuse ST-segment elevation with significant improvement within 3 hours. The peak level of high sensitivity cardiac troponin T was 1,546 ng/L. No alternative etiology of myocarditis was identified. Echocardiogram revealed mildly depressed left ventricular septal wall motion. Cardiac MRI showed abnormal native T1, T2 mapping, and extracellular volume (ECV) that were compatible with myocarditis. His symp-toms were relieved with ibuprofen. He was discharged on the fifth day of admission. In a 1-week follow-up, the ECG showed an incomplete right bundle branch block. Conclusion(s) This case illustrates the potential of myocarditis follow-ing mRNA COVID-19 vaccination with striking dynamic change and transition of the ECG. The possible mechanism for myocar-ditis after vaccination is molecular mimicry between viral spike protein and cardiac protein. More data and long-term follow-up are needed to understand the association between the COVID-19 vaccine and myopericarditis.