Clinical characteristics and prognostic impact of complicated phenotype in patients with acute myocarditis: a single-center registry study in china
J Wang, Yan-min YangAbstract
Background
Acute myocarditis (AM) exhibits significant variability in clinical presentation and prognosis, with limited data in China. This study aims to investigate the clinical characteristics, auxiliary examinations, treatment, and outcomes of AM patients in China.
Methods
In this single-center registry study, 204 patients diagnosed by histology or cardiac magnetic resonance (CMR) were included, comprising 36 prospectively enrolled cases (September 2022 to March 2024) and 168 retrospectively collected cases (January 2010 to March 2024). Patients were classified as complicated or uncomplicated according to the presence of left ventricular ejection fraction <50%, sustained ventricular tachycardia, and/or hemodynamic instability at presentation. The primary endpoint was cardiovascular death. Secondary endpoints included in-hospital death, all-cause death, cardiovascular readmission, and heart transplantation during 1-year follow-up.
Results
The average age of AM patients was 34.0±13.6 years, with a higher proportion of males (62.7%). At presentation, 9.8% of patients exhibited fulminant myocarditis, 57.4% developed heart failure, and 32.8% experienced arrhythmias. Of the 204 patients, 189 (92.6%) underwent baseline CMR, 86 (42.2%) received endomyocardial biopsy, 6 (2.9%) underwent in-hospital heart transplantation, and 6 (2.9%) experienced in-hospital death. During the 1-year follow-up, 11 patients (5.4%) experienced cardiovascular death, and 12 patients (6.3%) were readmitted due to cardiovascular causes. Complicated phenotype patients (n=100) were older (P<0.001), had a higher proportion of females (P=0.002), and were more likely to have fulminant myocarditis (P<0.001) compared to uncomplicated patients (n=104). The cardiovascular mortality rate and readmission rate for cardiovascular causes in complicated phenotype patients were 10.0% and 10.9%, respectively, compared to 1.0% and 2.0% in uncomplicated phenotype patients (P=0.004 and P=0.015). The risk of cardiovascular mortality increased with the number of criteria met for the complicated phenotype, with the highest risk observed in patients meeting ≥2 criteria, followed by those meeting 1 criterion, while patients meeting 0 criteria (uncomplicated phenotype) had the lowest risk (P=0.011). This trend remained statistically significant after adjusting for sex and age (P for trend=0.016).
Conclusions
For AM patients, meeting a greater number of complicated phenotype criteria is associated with a worse prognosis. This study provides important real-world evidence on the clinical characteristics and risk stratification of AM patients in China.figure 2