Early mortality-associated factors in pediatric fulminant myocarditis patients treated with venoarterial extracorporeal membrane oxygenation: a single-center retrospective cohort study.

Background: Fulminant myocarditis (FM) is a life-threatening pediatric condition that may progress rapidly to cardiogenic shock and multiorgan dysfunction. This study evaluated early clinical and laboratory factors associated with in-hospital mortality among pediatric FM patients treated with venoarterial extracorporeal membrane oxygenation (VA-ECMO). Methods: We retrospectively reviewed 44 consecutive children (<18 years) with FM treated with VA-ECMO from 2018 to 2025. Continuous variables are presented as median (interquartile range) and compared using the Mann-Whitney U test. Because only 7 deaths occurred, regression analyses were prespecified as exploratory. Least absolute shrinkage and selection operator (LASSO) was used for variable screening, followed by univariable and exploratory 3-variable logistic models. Receiver operating characteristic (ROC) analysis was used to describe discrimination of selected admission markers. Results: Thirty-seven patients survived to discharge and seven died in hospital, yielding an in-hospital survival rate of 84.1%. Compared with survivors, non-survivors had lower admission systolic blood pressure [73 (64-81) Conclusions: Admission SBP, LVEF, and BUN were early markers associated with in-hospital mortality in this single-center cohort of pediatric FM patients treated with VA-ECMO. These findings should be interpreted as hypothesis-generating rather than definitive prognostic evidence and require validation in larger multicenter cohorts.