Multiparametric CMR Findings in Mrna COVID-19 Vaccine-induced Myocardit is: A Case Series

ABSTRACT

Introduction: Within weeks of the pediatric coronavirus disease 2019 (COVID-19) vaccination campaign beginning, reports of acute myocarditis after adolescents' second vaccination began. The present research describes the clinical and cardiovascular magnetic resonance (CMR) imaging characteristics of three adolescents recently vaccinated with a mRNA vaccine and admitted for myopericarditis treatment. Case Description This retrospective case-series investigated adolescents admitted within a week of their second mRNA COVID-19 vaccination. The electronic medical record was queried for all patients ≥12 years old, admitted for acute myocarditis or pericarditis (International Classification Diseases-Version 10;I30.xx, I40.xx respectively) since April 1, 2021. Patients were included if they had a documented mRNA vaccination in the prior seven days. Three patients met inclusion criteria. All three had acute onset chest pain within 48 hours of receiving their second mRNA vaccine. All had elevated troponins, all were eventually admitted and had mild clinical courses. All met Lake Louise criteria for acute myocarditis despite only one patient having mild depression of cardiac function on echocardiography. All patients were negative for COVID-19 and none had a clinical history or immunologic evidence of prior COVID-19. The patient with the most diffuse pattern of late gadolinium enhancement on CMR (Figure 1) developed ventricular tachycardia three weeks after discharge. Discussion: Vaccine induced myopericarditis is rare in inactivated vaccines, but is a known entity with live vaccines, especially the smallpox vaccine. Since the 1950's, cases of myocarditis and pericarditis have been reported in association with vaccination. Research using VAERS has previously found that from 1990- 2018, 0.1% of reports were for myopericarditis associated with vaccination. The rates of mRNA vaccine-induced myocarditis are currently unknown, but our clinical findings are similar to other recently published case series of pediatric mRNA associated myopericarditis. We have observed differences in CMR patterns between our patients from this series and previous reports of patients with cardiac involvement from COVID-19 (Table 1). We remain uncertain regarding the precise pathophysiology in these patients with myocardial inflammation following mRNA vaccine administration. However, the relatively focal pattern of involvement, and the relative preservation of global function, suggest a milder involvement of the myocardium-in most of these patients-than has previously been observed in classic viral and COVID-19 myocarditis. Conclusion: Three adolescent males developed acute myocarditis within days of their second mRNA COVID-19 vaccination. CMR in combination with serum troponin measurements was critical for diagnosis, and arrythmia monitoring was critical in their follow up. Repeat CMR studies over the six months following diagnosis will be important to rule out development of post-inflammatory fibrosis and long-term arrhythmias. Legend A and B LGE (Magnitude IR) and PSIR (Phase sensitive IR), respectively, showing patchy epicardial enhancement at the basal inferolateral and inferior segments;C Abnormal ECV at basal anterolateral, inferolateral and inferior segments;D and E ECV and T1 bullseye maps with abnormal values;F and G Patchy visible edema at basal inferolateral, anterolateral and inferior segments on the T2 and T2 color map;H Bullseye map showing T2 values;I Asymmetric Right axillary lymphadenopathy secondary to vaccination in the right arm.