Objective:To investigate the risk factors of fulminant myocarditis in children.Methods:The clinical data of 67 children with clinical diagnosis of viral myocarditis from January 2015 to December 2018 in our hospital were retrospectively analyzed.The children were divided into fulminant myocarditis group( n=13)and common myocarditis group( n=54). The clinical data of gender, age, history of pre-infection, clinical manifestations, laboratory tests, electrocardiogram, echocardiography, and imaging findings were compared between the two groups.The multiple Logistic regression analysis was used to identify the independent risk factors of fulminant myocarditis. Results:(1)Seven cases(53.8%)died in the fulminant myocarditis group, 4 cases(30.8%) of them died within 24 hours after admission, and all the children in the common myocarditis group improved and discharged.(2)The incidences of facial cyanosis, abdominal distension, convulsions, and chills were higher in the fulminant myocarditis group than those in the common myocarditis group( P<0.05). (3)The level of creatinekinase-MB, lactate dehydrogenase, α-hydroxybutyric dehydrogenase and aspartate transferase in the fulminant myocarditis group were higher than those in the common myocarditis group( P<0.05). (4)On electrocardiogram, QRS wave duration in the fulminant myocarditis group was longer than that in the common myocarditis group[118(82, 127)ms vs.62(62, 122)ms, P<0.05]. The incidences of ventricular tachycardia in the fulminant myocarditis group was higher than that in the common myocarditis group( P<0.05). (5)In the fulminant myocarditis group, the incidences of left ventricular ejection fraction(LVEF)decreased, the left ventricular short axis fraction shortening(LVFS), and the incidence of left ventricular enlargement were higher than those in the common myocarditis group[92.3%(12/13)vs.18.5%(10/54), 84.6%(11/13)vs.9.3%(5/54), 76.9%(10/13)vs.13.0%(7/54), P<0.05]. Chest X-ray examination of the fulminant myocarditis group showed that the incidences of heart shadow enlargement and pulmonary blood stasis were higher than those in the common myocarditis group( P<0.05). (6)Multiple Logistic regression analysis revealed that LVEF reduction( OR=19.015, 95% CI 1.456-248.348, P=0.025), LVFS reduction( OR=18.691, 95% CI 2.062-169.453, P=0.009)and prolonged QRS wave duration( OR=1.040, 95% CI 1.001-1.082, P=0.046) were independent risk factors for fulminant myocarditis. Conclusion:The early mortality of fulminant myocarditis is high in children, and the LVEF reduction, LVFS reduction and prolonged QRS wave duration are independent risk factors for fulminant myocarditis.