Radiotherapy is safe in patients with implantable cardiac devices. Analysis of a systematic interrogation follow-up

The number of patients who have a cardiac implantable electronic device (CIEDs) that undergo a course of radiotherapy is increasing due to the ageing population. The majority of clinical studies only evaluate any CIED malfunction at the end of a course of irradiation or in a case of there being symptoms of possible malfunction. As a result, little data has been collected on CIED status acquired during an active course of irradiation.

We aimed to evaluate the correct functioning of a CIED during a course of radiotherapy. So, a retrospective analysis was made of all patients having CIEDS in a single institution during their course of radiotherapy. All CIEDs were systematically checked before and during the course of radiotherapy according to the risk of device failure and patient dependence.

Data was analysed from 56 patients (43 men, 13 women) with a mean age of 78.2 years, of whom 87.5% of the patients carried a pacemaker (PM), the 39% of the patients were PM dependent, and the remaining patients carried an implantable cardioverter-defibrillator (ICD). An observable dose of irradiation was evident in only 10 cases. 69.1% of the CIEDs were checked daily and the remainder were checked weekly. During the radiotherapy course, 82% of the patients did not complain of any cardiological event. The CIED of five patients experienced an increase in the threshold and, in another case, a sudden reduction in the duration of the battery was reported. Another patient with a CIED experienced a cardiac insufficiency episode triggered by a ventricular tachycardia.

In conclusions, although adverse clinical events from exposure of a CIED to irradiation are rare, they can appear in any group of risk. No dose-dependency was observed on the malfunction of the CIED.