Acute Myocarditis: Contemporary Diagnosis, Risk Stratification and Management, with a Focus on Heart Failure and Fulminant Presentations

Acute myocarditis encompasses a broad clinical spectrum, ranging from mild chest pain with preserved ventricular function to fulminant heart failure, malignant ventricular arrhythmias, cardiogenic shock and sudden cardiac death. Recent advances have shifted its definition from a primarily histopathological entity toward an integrated clinical syndrome in which multimodality imaging, biomarkers and endomyocardial biopsy contribute to diagnosis and risk assessment. Cardiac magnetic resonance has become central to non-invasive tissue characterization while endomyocardial biopsy remains a relevant approach in high-risk or treatment-refractory patients, allowing identification of histological subtypes that may require specific therapy. Management is largely determined by clinical severity and aetiology, ranging from supportive care and guideline-directed heart failure therapy to immunosuppression, targeted antimicrobial treatment and temporary mechanical circulatory support in fulminant cases. Increasing evidence also highlights the relationship between myocarditis-like episodes and inherited cardiomyopathies, particularly desmosomal disease, in which recurrent “hot phases” may represent an early manifestation of a genetic substrate. Based on a structured literature search, this narrative review summarizes current concepts in the classification, diagnosis, complications and management of acute myocarditis with particular emphasis on heart failure and fulminant presentations, risk stratification and genetic susceptibility. Throughout the text, established treatments are kept separate from emerging mechanism-based strategies, which are still supported by limited evidence.