Clinical and Cardiac Magnetic Resonance Imaging Findings in Pediatric Patients with Recurrent Viral Myocarditis.

Children and adults can suffer recurrence of myocarditis months to years after their initial presentation; however predictors of recurrence in the pediatric population have not been described to date. We sought to describe cardiac magnetic resonance (CMR) imaging findings and predictors of recurrence in a pediatric cohort. A retrospective cohort study of patients < 21 years, clinically diagnosed with acute myocarditis and who underwent CMR within 14 days of initial presentation was performed. Mann-Whitney U test and Fisher's exact test were used to compare those who fully recovered versus those with recurrence. Of 85 patients who met inclusion, median age 16.3 years (IQR 14.3, 17.5), 72 fully recovered, 5 had recurrence, 5 were lost to follow up and 3 progressed to chronic dilated cardiomyopathy. Median time to CMR following presentation was 2 days (IQR 2, 4) and time to recurrence was 681 days (IQR 386, 855). Compared to those who recovered, patients with recurrence had similar indices of ventricular function, volume, strain and tissue characterization including T1 mapping and T2 mapping on their initial and follow up CMR. Myocarditis may recur in a small proportion of children. These children have similar findings on initial and follow up CMR as those who recover. Further work is needed to identify useful predictors of recurrence in children.