Radiotherapy-induced Early ECG Changes and Their Comparison with Echocardiography in Patients with Early-stage Breast Cancer

Background: Early electrocardiogram (ECG) changes after breast cancer radiotherapy (RT) have been reported, but their characteristics and associated factors are largely unknown. This study aimed to explore early RT-induced ECG changes and to compare them with echocardiography changes. Materials and Methods: Sixty eligible patients with chemotherapy-naive left-sided and 20 with right-sided breast cancer were evaluated with echocardiography, blood samples and ECG before and after RT. Results: RT-induced ECG changes in the anterior leads. T-Wave changes were most frequent. T-Wave decline was associated independently with patient age (beta=-0.245, p=0.005), mean heart radiation dose (beta=1.252, p=0.001) and global systolic strain rate change (beta=7.943, p=0.002). T-Wave inversion was associated independently with mean heart radiation dose (beta=0.143, p<0.001), global longitudinal strain change (beta=0.053, p=0.017) and posterior calibrated integrated backscatter (beta=-0.022, p=0.049). Conclusion: RT-induced ECG changes were prevalent and associated with functional and structural changes in echocardiography. ECG could be used for post-RT cardiac screening.