The acute changes in parameters of cardiac implantable electronic devices in patients undergoing radiation therapy

The number of patients with cardiac implantable electronic devices (CIEDs) requiring effective cancer treatment, including radiotherapy (RT), is increasing year by year. A potentially harmful effect of RT on CIEDs depending on the type and physical parameters of radiation, location of the treated lesion, indications for electrotherapy, and the type of devices have been described in literature.

The aim of this study was to present short-time effect of radiotherapy on cardiac implantable electronic devices parameters.

We analyzed real-world data of patients with CIEDs underwent RT in a large, tertiary cardio-oncological centre between November 2016 and December 2023. Clinical, RT (localization of cancer, number of fractions, time of radiotherapy, cumulative dose, and dose per fraction) and CIED parameters from interrogation during first cardiologist consultation and after the last RT session (including type of CIED, pacing settings, and battery longevity, and device malfunction if any) were collected.

The study included 365 patients with CIEDs who had palliative or radical RT. Pacemakers were implanted in 281 patients, implantable cardioverter-defibrillators in 52, and devices with cardiac resynchronization therapy in 32, including two patients with left bundle branch pacing–optimized cardiac resynchronization therapy. Patient received cumulative dose up to 112 Gy per patient for the whole RT treatment (median [interquartile range], 36.25 [20–65] in about 10 fractions (10 [5-30]). In 55,8% of cases the tumor treated with radiotherapy were located under the diaphragm. All patients presented at cardiology consultations were admitted to radiotherapy. RT was administered without the need of device relocation. No device malfunctions or significant changes in battery longevity and lead parameters during radiotherapy were observed, except for the change in impedance at the LV electrode (p=0.04). However, these data were from a small group of patients (n=28) and were numerically not clinically significant. In individual cases, it was necessary to temporarily postpone radiotherapy due to the need to reposition the RV electrode, replace the device battery, plasty the implanted device pocket or extend invasive cardiological diagnostics.

Our analysis found no clinically significant changes in lead and battery parameters, indicating that radiotherapy for patients with CIEDs can be considered safe where appropriate precautions were implemented.

Clinical and radiotherapy characteristic