Most patients hospitalized with acute myocarditis experienced favorable long-term outcomes in a retrospective cohort study published in the Journal of Cardiac Failure, although older age, signs or symptoms of heart failure, and hypokinesia on echocardiography were associated with a higher risk of adverse events during follow-up.
The analysis included 471 consecutive patients hospitalized with acute myocarditis between 2009 and 2019. The median age was 34 years, and 32% of patients were women. Baseline clinical features, laboratory findings, echocardiographic data, and imaging results were systematically reviewed.
The primary composite endpoint included all-cause mortality, heart transplantation, mechanical circulatory support, new-onset heart failure, ventricular arrhythmias, and cardiac device implantation.

Findings

• Within 1 year, 41 patients (8.7%) experienced the composite outcome.
• Older age, dyspnea, and elevated biomarkers were associated with early adverse events.
• During a median follow-up of 8.2 years, increasing age remained independently associated with adverse outcomes (HR 1.05 per year; 95% CI 1.03-1.07).
• Signs or symptoms of heart failure were independently associated with adverse long-term outcomes (HR 3.27; 95% CI 1.25-8.52).
• Hypokinesia on echocardiography was independently associated with adverse outcomes during follow-up (HR 19.77; 95% CI 4.10-95.36).
• No significant sex-based differences in outcomes were observed despite differing clinical presentations (HR 0.78; 95% CI 0.31-1.96).

The findings suggest that most patients hospitalized with acute myocarditis experience favorable long-term outcomes, although early risk stratification may help identify individuals at higher risk for adverse events.