[Clinical characteristics and prognostic analysis of adult patients hospitalized with acute myocarditis].

<b>Objective:</b> To analyze the clinical characteristics of patients hospitalized with acute myocarditis and explore the relevant factors affecting the prognosis. <b>Methods:</b> This study was a retrospective cohort study. Patients with acute myocarditis hospitalized in the Second Affiliated Hospital of Harbin Medical University from March 2010 to October 2022 were included and divided into severe myocarditis group and non-severe myocarditis group according to clinical diagnosis results, retrospectively. Basic clinical features were collected and followed up in both groups. The primary endpoint was cardiac death and the secondary endpoint was cardiac re-hospitalization. According to the clinical outcome, Kaplan-Meier survival curve was drawn and assessed via log-rank <i>P</i> test. Cox proportional risk model was established to analyze the related factors affecting the prognosis of patients with acute myocarditis. <b>Results:</b> A total of 235 patients with acute myocarditis were included, including 138 males (58.7%), aged (34±16) years, 102 patients (43.4%) in the severe myocarditis group and 133 patients (56.6%) in the non-severe myocarditis group. Compared with the non-severe myocarditis group, the severe myocarditis group was older and had more clinical symptoms of dyspnea, edema, and syncope. At a follow-up of 3.8 (2.8, 4.8) years, cumulative cardiac mortality and cardiac readmissions in patients with acute myocarditis were 4.2% and 9.6%, respectively. Among them, patients with severe myocarditis had a higher risk of cardiac death and cardiac readmission than those without severe myocarditis (9.3% vs. 1.0%, log-rank <i>P</i>=0.004; 13.4% vs. 4.2%, log-rank <i>P</i>=0.021). Multivariate Cox analysis showed that the independent risk factor for cardiac death in patients with acute myocarditis was elevated serum creatinine level at baseline (<i>HR</i>=1.016, 95%<i>CI</i>: 1.003-1.028, <i>P</i>=0.013). Independent risk factors for cardiogenic readmission were increased left ventricular end-diastolic diameter on admission (<i>HR</i>=1.108, 95%<i>CI</i>: 1.035-1.187, <i>P</i>=0.003) and ventricular tachycardia or fibrillation during hospitalization (<i>HR</i>=6.563, 95%<i>CI</i>: 2.138-20.142, <i>P</i>=0.001). <b>Conclusions:</b> The patients with acute myocarditis had more clinical symptoms of dyspnea, edema, and syncope. Elevated serum creatinine level on admission was an independent risk factor for cardiac death in patients with acute myocarditis; increased end-left ventricular diameter on admission and ventricular tachycardia or fibrillation during hospitalization were independently associated with cardiac rehospitalization.