Inflammatory cardiomyopathy: Position paper of the Italian Society of Cardiology Working Group on cardiomyopathies and pericardial diseases in collaboration with the Italian Society of Cardiology Working Group on cardiac magnetic resonance

Inflammatory cardiomyopathy (iCMP) usually represents the chronic, hypokinetic phenotype within the myocarditis spectrum, characterized by persistent myocardial inflammation, systolic ventricular dysfunction, and adverse remodelling. It frequently evolves from prior acute or subacute myocarditis and is associated with significantly worse outcomes, including progression to dilated cardiomyopathy, heart failure, and arrhythmias. The condition arises from heterogeneous causes-infectious, autoimmune, or idiopathic-and may be influenced by genetic susceptibility, supporting a two-hit model in which environmental triggers interact with pathogenic variants. Diagnosis requires a multimodal approach. While clinical presentation is variable and often non-specific, cardiac magnetic resonance (CMR) provides essential tissue characterization, enabling detection of inflammation and fibrosis. Endomyocardial biopsy (EMB) remains critical for defining histologic subtype, identifying viral genomes, and guiding targeted therapy, especially in intermediate- or high-risk cases. Genetic testing assists in differentiating inherited CMPs and recognizing forms with distinctive inflammatory behavior, such as desmoplakin CMP. Management focuses on guideline-directed medical therapy for heart failure and treatment of underlying aetiologies. In biopsy-proven, virus-negative iCMP, immunosuppressive therapy may improve ventricular function and limit adverse remodelling, while antiviral strategies remain reserved for selected virus-positive cases. Arrhythmia management, including ICD implantation, is essential in patients with substantial fibrotic burden or arrhythmias. Prognosis depends on ventricular function, extent of fibrosis, viral persistence, arrhythmic burden, and recurrence of inflammatory "hot phases." Lifelong follow-up is warranted. This position paper provides a comprehensive framework for the diagnosis, risk stratification, and management of iCMP, highlighting current evidence, guideline alignment, and remaining gaps.