Highly suspected fulminant myocarditis induced by the immune checkpoint inhibitor tislelizumab: a case report with third-degree atrioventricular block and recurrent ventricular tachycardia

ICI-associated myocarditis is characterized by a low incidence but carries a high risk of fatal outcomes. Early recognition of severe cases and timely intervention can substantially improve prognosis. In this case, fulminant myocarditis related to the ICI tislelizumab was highly suspected but not pathologically confirmed, as cardiac magnetic resonance imaging and endomyocardial biopsy were not performed. Despite this limitation, the case may still provide a useful clinical reference for the diagnosis and management of severe ICI-associated myocarditis.