Electrocardiographic changes in immune checkpoint inhibitor-associated cardiac injury: a narrative review.

Background and Objective: Immune checkpoint inhibitors (ICIs) are widely used in cancer treatment and have shown substantial clinical benefit. Although the incidence of ICI-associated cardiac injury is uncommon, such events may lead to severe complications and high mortality. Current tools for evaluating cardiac injury include serum biomarkers, electrocardiogram (ECG), echocardiography, cardiac magnetic resonance imaging, coronary angiography, and endomyocardial biopsy. Among these, ECG is widely used because of its convenience and practicality and serves as an important screening tool. This review summarizes ECG manifestations associated with ICI-associated cardiac injury to further clarify the clinical role of ECG in this setting. Methods: A literature search was conducted in PubMed for English-language literature published from February 23, 2010 to February 13, 2026 using predefined keywords related to immune checkpoint inhibitors, ECG, and cardiac injury. Key Content and Findings: ECG, as a diagnostic and monitoring tool for cardiotoxicity, has both advantages and limitations. Common ECG manifestations include arrhythmias such as premature atrial contractions, premature ventricular contractions, atrial fibrillation or atrial flutter, ventricular tachycardia (or ventricular fibrillation), and atrioventricular block, as well as QRS complex prolongation, low QRS voltage, and ST-segment and T-wave (ST-T) abnormalities. Among these findings, conduction disturbances, tachyarrhythmias (particularly ventricular tachycardia), and ST-T segment abnormalities are associated with higher mortality. However, ECG alone has limited diagnostic specificity, and its value is improved when combined with other diagnostic modalities. Conclusions: ECG is an important noninvasive tool for monitoring ICI-associated cardiac injury and plays a crucial role in screening and diagnosis. However, important knowledge gaps remain, including the lack of specific ECG markers for early diagnosis, limited evidence on ECG features that distinguish ICI-associated myocarditis from other causes of cardiac injury, insufficient understanding of the temporal evolution of ECG abnormalities, and the absence of validated ECG-based risk stratification or early warning models. Future research should focus on the development of early prediction models and further elucidation of injury mechanisms to improve cardiac safety during ICI therapy.