Incidence of Radiotherapy Induced Cardiac Implantable Electronic Devices Malfunction: Australian-Based Observation Study.

Abstract

To assess the incidence rate of cardiac implantable electronic devices (CIED) malfunction with radiotherapy (RT) and identify factors resulting in CIED malfunction. The working hypothesis is that CIED malfunction is associated with higher photon beam energy, treatment anatomical location, device type and dose to device. This retrospective review involved 441 patients with CIED treated with RT. Clinical information, RT (prescription, dose to device, beam energy, anatomical regions treated etc.) and CIED details (type, manufacturer, and device malfunction) were collected from electronic medical records. A total of 344 patients (78%) had a permanent pacemaker (PPM), 44 patients (10%) had implantable cardioverter defibrillator (ICD), 44 patients (10%) had CRT-defibrillator (CRT-D) and 9 (2%) had cardiac resynchronization therapy-pacing (CRT-P). The median prescribed dose was 36 Gy (IQR 1.8-80 Gy). 17 out of 441 patients (3.9%) experienced an CIED malfunction event. This group had a higher prescribed median dose of 42.5 Gy (IQR 20-77 Gy) and beam energy of 14 MV (12-18 MV). None of the malfunctions resulted in clinical symptoms. Median dose to CIED was 0.28 Gy (IQR 0-3.3). No patents received dose to device ≥2 Gy. Using logistic regression, the predictors of CIED malfunction were photon beam energy use ≥10 MV (OR 5.73; 95% CI, 1.58-10.76), anatomical location of RT above the diaphragm (OR 5.2, 95% CI, 1.82-15.2), and having an ICD (OR 4.6, 95% CI, 0.75-10.2). We have demonstrated that photon beam energies ≥10 MV, RT to above the diaphragm and ICD devices are significantly associated with CIED malfunction. The recorded CIED malfunctions in this study were minor malfunctions which did not result in any clinical symptoms. Stringent adherence to the local institution's CIED treatment guidelines, utilization of safety measures and careful choice of beam energy are recommended to minimize risk of symptomatic CIED malfunctions.