Introduction
Myopericarditis is a rare side effect following messenger ribonucleic acid (mRNA) COVID-19 vaccination. Cardiac magnetic resonance (CMR) imaging can detect myopericarditis with high sensitivity and resolution of CMR abnormalities mirrors clinical improvement.
Methods
Patients presenting with Pfizer vaccine induced myocarditis were assessed with CMR at index presentation and post-discharge.
Results
Twenty-one patients, mean age 25.7+/-8.0yrs (95.2% male), were admitted to our health service between September 2021 and March 2022 with myocarditis following Pfizer COVID-19 vaccination, 90.5% after the second and 9.5% after the third (booster) dose. Chest pain (100%), fever (61.9%), myalgia (47.6%) and dyspnoea (33.3%) developed at a median of 2 days post-vaccination. Mean troponin was 864ng/mL (72-4532 ng/mL), CRP 47mg/L (2.7-160mg/L) and BNP 531ng/mL (52-1686 ng/mL). Electrocardiographic changes of widespread ST segment elevation were present in 66.7% and PR depression in 14.2% of cases. CMR was performed in 90.5% of patients. Myocardial oedema was demonstrated in all patients, and late gadolinium enhancement (LGE) in 94.7% of patients, predominantly subepicardial involving the inferolateral segments. Left ventricular ejection fraction (LVEF) was reduced in 26.3% of patients (mean LVEF 52.1+/-4.7% and RVEF 50.1+/-4.5%). Extensive myocardial LGE was present in one patient who developed cardiogenic shock requiring extracorporeal supportive therapy before making a full recovery. All other patients had a mild clinical course. To date, follow up CMR scans performed in 38.1% of patients have all demonstrated significant reduction in LGE compared to baseline.
Conclusion
Myocarditis following mRNA COVID-19 vaccination is associated with CMR changes which resolve over time.
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