AbstractIn this study, we sought predictors of mortality in children with acute myocarditis and of incomplete recovery in the survivor group. We classified our patients into three groups according to their outcomes at last follow-up: full recovery was classified as group I, incomplete recovery was classified as group II, and death was classified as group III. In total, 55 patients were enrolled in the study: 33 patients in group I, 11 patients in group II, and 11 patients in group III. The initial left ventricular fractional shortening – left ventricular fractional shortening – was significantly lower in group III (p=0.001), and the left ventricular end-diastolic dimension z score was higher in groups II and III compared with group I (p=0.000). A multivariate analysis showed that the left ventricular end-diastolic dimension z score (odds ratio (OR), 1.251; 95% confidence interval (CI), 1.004–1.559), extracorporeal membrane oxygenation (OR, 9.842; 95% CI, 1.044–92.764), and epinephrine infusion (OR, 18.552; 95% CI, 1.759–195.705) were significant predictors of mortality. The left ventricular end-diastolic dimension z score was the only factor that predicted incomplete recovery in the survivor group (OR, 1.360; 95% CI, 1.066–1.734; p=0.013). The receiver operating characteristic curve of the left ventricular end-diastolic dimension z score at admission showed a cut-off level of 3.01 for predicting mortality (95% CI, 0.714–0.948). In conclusion, a high left ventricular end-diastolic dimension z score on admission was a significant predictor of worse outcomes, both regarding mortality and incomplete recovery.