Arrhythmic Risk in Myocarditis Outcome Research

Incidence, Clinical Impact, and Prediction of Ventricular Arrhythmia in Patients With Acute Myocarditis

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

Inclusion Criteria:

• Age ≥ 18 years
• Hospitalization for acute myocarditis
• Confirmation of the diagnosis of AM by at least one of the following: (1) Cardiac magnetic resonance according to the revised 2018 Lake Louise Criteria; (2) Endomyocardial biopsy according to the Dallas criteria with associated immunohistochemical and molecular criteria; (3) Cardiac computed tomography with compatible late iodine enhancement

Exclusion Criteria:

• Age < 18 years
• Concomitant acute coronary syndrome