Pediatric Myocarditis: Contemporary Insights Into Viral and Immune-Mediated Pathobiology, Precision Diagnostics, Advanced Multimodality Imaging, Risk Stratification, and Evolving Therapeutic Strategies

Pediatric myocarditis is an important cause of acute and chronic myocardial dysfunction, accounting for a substantial proportion of dilated cardiomyopathy, heart failure, malignant arrhythmias, and sudden cardiac death in children. Although historically considered a predominantly viral disease, contemporary evidence indicates that pediatric myocarditis represents a heterogeneous spectrum of disorders characterized by complex interactions between infectious triggers, innate and adaptive immune responses, host genetic susceptibility, and myocardial repair mechanisms. The emergence of multisystem inflammatory syndrome in children and vaccine-associated myocarditis has further expanded the clinical spectrum while emphasizing the importance of accurate etiologic classification. Diagnosis remains challenging because clinical manifestations range from mild chest discomfort to fulminant cardiogenic shock. Advances in high-sensitivity cardiac troponin assays, cardiac magnetic resonance imaging with multiparametric tissue characterization, molecular pathogen detection, and selective endomyocardial biopsy have substantially improved diagnostic accuracy. Risk stratification increasingly integrates clinical presentation, ventricular function, biomarker profiles, arrhythmic burden, and imaging findings to identify patients at risk for adverse outcomes and guide therapeutic intensity. Contemporary management combines evidence-based heart failure therapy with individualized immunomodulatory treatment, mechanical circulatory support for refractory cardiogenic shock, and multidisciplinary long-term surveillance. Although survival has improved significantly with advances in pediatric intensive care and ventricular assist devices, important uncertainties remain regarding optimal immunotherapy, biomarker-guided management, and precision medicine approaches. This narrative review summarizes current understanding of viral and immune-mediated pathobiology, discusses evolving diagnostic strategies and multimodality imaging, reviews contemporary risk stratification models, and highlights emerging therapeutic approaches aimed at improving outcomes in children with myocarditis.