Myocarditis and look-alikes: when the diagnosis matters

HeartPublished 20 Jan 2026

Study context

Population: Five conditions presenting with or mimicking myocarditis that require targeted diagnostic approaches, including endomyocardial biopsy, and/or targeted treatments

Comparison: Giant cell myocarditis vs Myocarditis related to immune checkpoint inhibitors vs Eosinophilic myocarditis vs systemic immune-mediated inflammatory diseases vs Genetic pathogenic mutations in desmoplakin and other desmosomal genes

Giant cell myocarditis: an intense and unresolving inflammation of the heart, characterised by rapid progression, significant arrhythmias, heart failure and shock, that is unlikely to resolve without immunosuppression therapy
Myocarditis related to immune checkpoint inhibitors: a rare but potentially fatal adverse effect of the use of cancer immunotherapy with checkpoint inhibitors, requiring immunosuppressive therapy
Eosinophilic myocarditis: can be triggered by allergy, hypersensitivity reactions, infections or can be idiopathic and is characterised by eosinophilic infiltrates in the heart and other organs, associated with thrombosis and necessitating targeted therapy
systemic immune-mediated inflammatory diseases: Myocarditis is a frequent cardiovascular manifestation of systemic immune-mediated inflammatory diseases such as systemic lupus erythematosus; injury is caused by an autoimmune response in the myocardium and cytokine-mediated damage, requiring targeted therapy
Genetic pathogenic mutations in desmoplakin and other desmosomal genes: can present with ‘hot phases’ mimicking myocarditis associated with an increased risk of arrhythmias, heart failure, and sudden cardiac death

Myocarditis and look-alikes: when the diagnosis matters. Heart. Published 20 January 2026. doi:10.1136/heartjnl-2025-326381

Summarised from the published abstract; every number is checked against it