Arrhythmic Risk in Myocarditis Outcome Research

The goal of this observational, retrospective, multicenter study is to characterize the arrhythmic burden and identify predictive factors for ventricular arrhythmias (VAs) in adult patients hospitalized for acute myocarditis (AM). The main questions it aims to answer are: * What is the incidence of sustained ventricular arrhythmias during the index hospitalization in patients with acute myocarditis? * What clinical, biological, electrocardiographic, and imaging factors predict the occurrence of sustained ventricular arrhythmias during hospitalization and after discharge? Researchers will compare patients who developed sustained VAs during hospitalization to those who did not, in order to identify independent predictors of arrhythmic events and develop a validated risk stratification score. Participants' medical records from 2020 to 2024 will be reviewed to collect: * Baseline demographic, clinical, biological, electrocardiographic, and imaging data at admission * In-hospital management strategies and outcomes, including mortality, cardiogenic shock, and heart replacement therapy * Long-term follow-up data including VA recurrence, sudden cardiac death, and development of cardiomyopathy, with censoring applied on January 1, 2026