Long-term Prognosis and Early Clinical Predictors in Acute Myocarditis: Insights from a 10-year, Unselected Hospital...

Acute myocarditis is an inflammatory cardiac condition with a variable prognosis, ranging from complete recovery to progressive heart failure (HF) or death. Advances in diagnostics, such as high-sensitivity troponins and cardiac magnetic resonance (CMR), have improved detection, but prognostic insights in unselected, real-world populations remain limited.

We retrospectively studied 471 consecutive patients hospitalized with acute myocarditis between 2009 and 2019, based on clinical diagnosis. Baseline features, laboratory results, and imaging data were systematically reviewed. The primary composite outcome included all-cause mortality, heart transplantation, mechanical circulatory support, new-onset HF, ventricular arrhythmias, and cardiac device implantation. The median patient age was 34 years and 32% were female. Chest pain was the predominant presenting symptom (87%), and ST-segment elevation was observed in 48%. At admission, 24% showed hypokinesia on echocardiography, and 12% had a left ventricular ejection fraction of <50%. Within 1 year, 41 patients (8.7%) experienced the composite outcome. Older age, dyspnea, and elevated biomarkers were associated with early events. Over a median follow-up of 8.2 years, independent predictors of adverse outcomes were age (hazard ratio [HR] 1.05 per year, 95% confidence interval [CI] 1.03-1.07), signs/symptoms of HF (HR 3.27, 95% CI 1.25-8.52), and hypokinesia on echocardiography (HR 19.77, 95% CI 4.10-95.36). No sex-based differences in outcomes were found despite different clinical presentations (HR 0.78, 95% CI 0.31-1.96).

In this decade-long cohort, most patients had favorable outcomes. Early risk stratification and targeted management may improve prognosis in high-risk individuals.