Cardiac adverse reactions of COVID-19 vaccination: cardiac MRI findings

BACKGROUND: The rapid development of COVID-19 vaccines in the wake of the COVID-19 pandemic has led to an equally expediently deployed vaccination campaign with more than 12 billion vaccinations administered worldwide. Reports of vaccine-associated adverse reactions (VAARs) have ranged from headaches and pain at the injection site to potentially life-threatening events such as cerebral venous sinus thrombosis. The heart has also not been spared of VAARs, as vaccine-associated myocardial infarction and more commonly, albeit still rare, myocarditis and perimyocarditis have been reported in predominantly young male recipients. METHODOLOGICAL INNOVATIONS: Cardiac magnetic resonance imaging findings of vaccine-associated myocarditis such as prolonged T1 and T2 relaxation times, increased T2 signal intensity ratio, and subepicardial late gadolinium enhancement have been demonstrated to be similar to those in virus-induced myocarditis, enabling the use of the modified 2018 Lake Louise Criteria for diagnostic purposes to confirm vaccination-associated myocardial inflammation. Other reported cardiac findings such as cardiomyopathies and arrhythmias were confined to case reports. The incidence of myocardial infarction was not noted to be higher than in the overall population. CONCLUSION: The overall preliminary prognosis of vaccine- associated myocarditis seems to be good as suggested by initial reports, but long-term follow-up is needed to sufficiently assess possible sequelae and consequences.