Patients with Post-COVID-19 Vaccination Myocarditis Have More Favorable Strain in Cardiac Magnetic Resonance Than Those With Viral Myocarditis.

There have been reports of myocarditis following vaccination against COVID-19. We sought to describe cardiac magnetic resonance (CMR) findings among pediatric patients. Retrospective review at a large academic center of patients clinically diagnosed with post-vaccine myocarditis (PVM) undergoing CMR. Data collected included parametric mapping, ventricular function, and degree of late gadolinium enhancement (LGE). Post-processing strain analysis was performed using feature tracking. Strain values, T1/T2 values, and ventricular function were compared to age- and gender-matched controls with viral myocarditis using a Wilcoxon Signed Rank test. Among 12 patients with presumed PVM, 11 were male and 11 presented after the second vaccination dose, typically within 4 days. All presented with chest pain and elevated troponin. 10 met MRI criteria for acute myocarditis. All had LGE typically seen in the lateral and inferior walls; only five had prolonged T1 values. 10 met criteria for edema based on skeletal muscle to myocardium signal intensity ratio and only 5 had prolonged T2 mapping values. Patients with PVM had greater short-axis global circumferential and radial strain, right ventricle function, and cardiac output when compared to those with viral myocarditis. Patients with PVM have greater short-axis global circumferential and radial strains compared to those with viral myocarditis. LGE was universal in our cohort. Signal intensity ratios between skeletal muscle and myocardium may be more sensitive in identifying edema than T2 mapping. Overall, the impact on myocardial strain by CMR is less significant in PVM compared to more classic viral myocarditis.

Asymmetric septal edema masking as hypertrophy in an infant with COVID-19 myocarditis.

Cardiac disease in pediatric patients due to coronavirus SARS-CoV-2 disease (COVID-19) includes myocarditis and multisystem inflammatory syndrome, both of which can present with a broad range in severity. Here we describe an infant with COVID-19 causing fulminant myocarditis with inotrope-resistant acute heart failure requiring extracorporeal membrane oxygenation. The patient demonstrated an atypical finding of localized septal thickening suggestive of hypertrophic cardiomyopathy, but the diagnosis of myocarditis was confirmed by cardiac MRI. Serial echocardiography illustrated complete resolution of septal hypertrophy and normalized cardiac function. The current report highlights the potential severity of COVID-19 associated myocarditis, the potential for recovery, and the utility of cardiac MRI in confirming the mechanism.