LAUSR

Purpose Though many pediatric centers use immunotherapy including immunoglobulin (IVIG) and corticosteroids to treat patients with acute myocarditis, given a lack of evidence supporting its efficacy there is considerable variability in practice. We report our approach using high dose steroids with IVIG to treat acute myocarditis. Methods This is a single center retrospective observational study of children diagnosed with myocarditis treated with high dose steroids and IVIG from January 2004-April 2020. Diagnostic criteria for myocarditis included positive endomyocardial biopsy, MRI meeting Lake Louise criteria, or clinical diagnosis including an elevated troponin, LVEDD Z score Results ty one patients met inclusion criteria. Median age at diagnosis was 10.7 years (1 wk-20 yrs). The majority were male (65%). Diagnosis was made clinically in 68% of cases (N=21), MRI in 16% (N=5) and biopsy in 16% (N=5). Ten patients had positive respiratory viral PCR, 6 had positive plasma viral PCR and 0 had positive biopsy viral PCR. Median EF at diagnosis was 41% (IQR 10-65). Mean duration of steroids received was 74 days (SD 13) with IV steroids for 7 days (IQR 3-13) prior to transition to an enteral regimen. The mean cumulative dose of steroids for first 7 days was 38 mg/kg. All patients received IVIG; median cumulative dose was 2 g/kg. Seven patients (23%) required mechanical circulatory support (5 ECMO, 1 Centrimag LVAD and 1 Centrimag BiVAD). There were no serious secondary bacterial. In-hospital mortality was 0%. Mean follow up was 2 years (SD=2yr); 1 patient died 2 years after discharge; 1 patient underwent transplant during initial hospitalization; no others were listed. Five required re-admission for cardiovascular reasons. Six patients (19%) had steroid course altered due to suspected side effects such as weight gain or hypertension which resolved at follow up. By 3 months from diagnosis, 84% (N=26) of patients regained normal LV function. Conclusion Our study demonstrates that use of high dose steroids with IVIG to treat myocarditis can be safe without significant infections or side effects. Our cohort had excellent recovery of ventricular function and survival without transplant (94%). Prospective comparison of a combination of high dose steroids with IVIG versus either therapy alone is needed.