Clinical characteristics and related risk factors in nonfulminant myocarditis children with adverse cardiovascular events: a restrospective cohort study

Objective Data about risk factors for major adverse cardiac event (MACE) in children with nonfulminant myocarditis (NFM) is limited. Therefore, we aimed to analyze the clinical characteristics and risk factors for MACE in children with NFM admitted to Beijing Anzhen Hospital in the past 10 years. Methods This was a single-center, retrospective cohort study. Children with NFM and followed up for 12 months after discharge who were admitted to Beijing Anzhen Hospital from January 2009 to January 2018 were included. Based on the presence of MACE recorded during follow-up, all NFM children were divided into the poor prognosis group and the control group. Clinical characteristics were compared between groups. The primary outcome was the risk factors of MACE (the composite rate of all-cause mortality, hospitalization for heart failure, and adverse arrhythmia). Results Among the 551 children with NFM, 14.3% of NFM children were associated with MACE; therefore 79 were in the poor prognosis group, and 472 were in the control group. Children in the poor prognosis group were usually younger, had shorter disease duration, more frequently had wheezing, fatigue, with increased rates of arrhythmia, worse inflammation, decreased cardiac function, and higher application rate of drugs (all P <0.05). Besides, rates of decreased wall motion, heart enlargement, myocardial edema, pericardial effusion, and delayed gadolinium enhancement (LGE) were significantly increased in NFM children at admission, 6 and 12 months after discharge (all P <0.05). Multivariate Cox regression analysis showed that troponin I (HR = 1.815, 95% CI: 1.124−2.931), brain natriuretic peptide (HR = 2.367, 95% CI: 1.337−3.859), LVEF (HR = 0.741, 95% CI: 0.582−0.943), pericardial effusion (HR = 2.473, 95% CI: 1.359−4.501), and delayed gadolinium enhancement (HR = 3.117, 95% CI: 1.724−5.636) were independent risk factors for MACE. Conclusion NFM children with MACE are usually young, have wheezing, fatigue, and increased incidences of worse inflammation, arrhythmia and depressed ventricular function. Besides, troponin I, brain natriuretic peptide, LVEF, pericardial effusion, and LGE are risk factors for MACE.