Background: Immune checkpoint inhibitors (ICI) have revolutionized cancer therapy and significantly improved cancer-related survival. However, their use has been associated with increased morbidity and mortality due to cancer therapy–related cardiovascular toxicity (CTR-CVT). Among these toxicities, arrhythmias have emerged as a relevant clinical manifestation, yet their prevalence and characteristics in patients treated under ICIs remain insufficiently explored.
Aim: This study aims to describe the prevalence and incidence of ICI-therapy-related arrhythmias.
Methods: The study included adult patients treated with ICIs for various malignancies from the local EcoR Registry. Arrhythmias included atrial fibrillation, supraventricular tachycardia, bradycardia, QT prolongation (>480 ms), supraventricular extrasystoles, ventricular extrasystoles, and ventricular tachycardia. Patients underwent comprehensive cardiac evaluations every 3–6 months, including clinical assessment, ECG, echocardiography, and biomarkers (high-sensitivity troponin, NT-proBNP), with additional arrhythmia screening by long-term ECG, device interrogation, and hospital records, according to 2022 ESC Cardio-Oncology Guidelines.
Results: A total of 617 patients (49% male, 63 ± 14 years) receiving immune checkpoint inhibitor therapy were screened for arrhythmias. Melanoma was the most frequent cancer type (67%). Dual ICI therapy was administered in 20% (122/617) of patients, while overall cardiovascular toxicity occurred in 38% (236/617) of patients. At baseline, cumulative arrhythmias were documented in 11% (68/617) of patients, increasing to 22.8% (141/617) during a 2-year follow-up period (McNemar, p-value < 0.05). After a two-year follow-up, the prevalence of atrial fibrillation increased from 5,3% (33/617) to 7,7% (47/617), while the supraventricular tachycardia rate rose from 4,1% (25/617) to 9,3% (57/617) of screened patients. Sinus bradycardia was observed in 2,2% (13/617) of patients initially and in 6,8% (42/617) at the end of follow-up. A QT prolongation (>480 ms) was also increased from 3,1% (19/617) to 8,1% (50/617) during follow-up. No significant ventricular arrhythmias were detected. The co-occurrence analysis of arrhythmia types did not reveal any frequent arrhythmia patterns. Interestingly, Kaplan–Meier analysis demonstrated significantly better survival in the non-arrhythmia group than in the arrhythmia group (log-rank p = 0.006).
Conclusion: New-onset arrhythmias occurred more frequently during ICI therapy, indicating a potential relationship between ICI and cardiac rhythm disturbances. Patients who developed arrhythmias had poorer survival outcomes.
