[Arrhythmias and electrocardiographic characteristics in cancer patients treated with immune checkpoint inhibitors].

Objective

To evaluate the incidence of arrhythmias and electrocardiographic (ECG) characteristics in cancer patients treated with immune checkpoint inhibitors (ICIs).

Methods

This was a cohort study conducted in the Fourth Hospital of Hebei Medical University. Cancer patients initiating ICIs treatments from November 2020 to September 2022 were included in this study. Baseline 12-leads ECG before ICIs initiation and post-treatment ECG were analyzed. An abnormal ECG was defined as the presence of any of the following changes: sinus arrhythmias, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia, ventricular tachycardia, premature contractions, conduction disorder, and ST-T changes.

Results

A total of 87 patients were enrolled, aged 63 (57, 68) years, with 66 (75.9%) males. And 44.8% (39/87) of patients presented with at least one confirmed cardiovascular disease or cardiovascular risk factor at baseline. The incidence of abnormal ECG increased from 31.0% (27/87) at baseline to 65.5% (57/87) after receiving (5.0±2.7) cycles of ICIs treatment (P<0.001). The incidence of sinus arrhythmias was significantly increased after ICIs treatment (23.0% (20/87) vs. 9.2% (8/87), P=0.023), of which only the incidence of sinus tachycardia was significantly increased (11.5% (10/87) vs. 2.3% (2/87), P=0.039). There was also a significantly increased incidence of ST-T changes after ICIs treatment (31.0% (27/87) vs. 17.2% (15/87), P=0.012), which mainly attributed to the T wave changes (29.9% (26/87) vs. 13.8% (12/87), P=0.001). The incidence of premature contractions was also significantly increased after ICIs treatment (9.2% (8/87) vs. 0, P=0.008). Additionally, compared with baseline, the P wave axis was significantly increased after ICIs treatment ((56.94±21.01)° vs. (52.00±22.69)°, P=0.043). After ICIs treatment, the heart rate was significantly increased ((79.07±15.37) beats/min vs. (75.64±13.37) beats/min, P=0.029). Sokolow-Lyon index ((2.21±0.81)mV vs. (2.33±0.75)mV, P=0.138), QTc interval ((431.44±36.04)ms vs. (428.00±30.05)ms, P=0.415) all showed signs of change after treatment, but did not reach the traditional significant level.

Conclusions

The incidence of abnormal ECG is significantly increased after ICIs treatment, especially for sinus tachycardia, premature contractions and T wave changes; the P wave axis and heart rate is also significantly increased after treatment. It is important to perform regular ECG monitoring in patients receiving ICIs treatment.