Clinical Features, Treatment, and Outcomes of Sintilimab-Induced Myocarditis

To examine the clinical characteristics of sintilimab-induced myocarditis and to provide evidence for its diagnosis and management. Retrospective analysis was conducted on clinical case reports of sintilimab-induced myocarditis documented before July 31, 2025. A total of 34 patients were included, with a median age of 64 years (range: 33–85), including 23 (67.6%) male cases. The onset of myocarditis ranged from 1 to 120 days post-treatment, with a median onset of 21 days. The primary clinical presentations included dyspnea (41.2%), chest tightness (35.3%), palpitations (17.6%), and shortness of breath (14.7%), with some cases remaining asymptomatic (8.8%). Comorbid immune-related adverse events included myasthenia gravis (44.1%), myositis (17.6%), and hepatitis (17.6%). Laboratory findings often revealed elevated cardiac troponin I, N-terminal probrain natriuretic peptide, creatine kinase MB, and lactate dehydrogenase. The electrocardiogram mainly showed atrioventricular block (41.2%), ST-T segment changes (44.1%), and atrial or ventricular arrhythmias (50.0%). Echocardiography examination can show normal (34.5%), left ventricular diastolic dysfunction (31.0%), left atrial enlargement (13.8%), and pericardial effusion (13.8%). Cardiac magnetic resonance imaging may show normal (42.9%), myocardial edema (28.6%), and delayed myocardial enhancement (28.6%). Coronary angiography showed normal (73.3%) and coronary artery stenosis of the lumen (26.7%). All patients discontinued sintilimab and received steroid and intravenous immunoglobulin treatment. Outcomes indicated that 79.4% recovered from myocarditis, while 20.6% succumbed. Sintilimab-induced myocarditis has nonspecific manifestations and a high mortality rate. Myasthenia gravis and myositis can occur simultaneously with myocarditis. During simtimab treatment, it is necessary to closely monitor cardiac parameters and symptoms.