Search

Introduction:The effects of radiotherapy (RT) on cardiac implantable devices (CIEDs) (pacemakers, PMs, or implantable cardioverter-defibrillators, ICDs), are unpredictable. CIED function may be impaired during direct exposure, with harmful failures in PM-dependent or ICD patients.Hypothesis:To evaluate CIED malfunctions during direct RT exposure to doses up to 10 Gy, 53 wireless-enabled CIEDs (17 PMs and 36 ICDs) were evaluated in three different centers.Methods:After baseline interrogation, single chamber devices were set in the VVI/40 mode while dual or triple chamber ones in the DDD/40 mode. In ICDs, antitachycardia therapies were disabled, with the ventricular tachycardia (VT)/ventricular fibrillation (VF) monitor still active. A centering CT was performed to build the corresponding treatment plan and the CIEDs were blinded randomized to receive either 2, 5 or 10 Gy RT by a 6 MV Linac in a water phantom. The dose received by the CIEDs was assessed by an in-vivo dosimetry. During RT, each of the CIEDs was observed in a real-time session using manufacturer specific programmer, and pacing and sensing issues, noise interferences, or detections were recorded by a video camera in the bunker during exposure.Results:13 PMs (24.5% overall; 76.5% among PMs) recorded minor electromagnetic interferences, and no oversensing nor pacing inhibition were observed. 4 PMs (7.5% overall; 23.5% among PMs) reported neither transient malfunction nor minor noise. Almost all ICDs (60.4%% overall; 88.8% among ICDs) recorded electromagnetic interferences, 16 ICDs (30.2% overall; 44.4% among ICDs) reporting noise-related pacing inhibition and VT/VF detections. 16 ICDs (30.2% overall; 44.4% among ICDs) recorded minor noise, with any detections being observed. 4 ICDs (7.5% overall; 11.2% among ICDs) reported neither transient malfunction nor minor noise. Transient malfunctions occurred regardless of exposure dose.Conclusions:Electromagnetic interferences were observed in the majority of the CIEDs all through RT exposure. In high risk patients (PM-dependent or ICD ones), to avoid potentially life-threatening CIED malfunctions, magnet application on the pocket site or reprogramming should still be considered during even low energy RT exposure.

Introduction:Oncologic radiotherapy (RT) in patients with cardiac implantable electronic devices (CIEDs), both pacemakers (PMs) or implantable cardioverter defibrillators (ICDs), remains still troubleshooting. Unlike magnetic resonance imaging, high dose photon radiation, at even less than 6MV power, may transiently or permanently affect normal device function. To evaluate CIED malfunctions by direct exposure to oncologic RT at doses up to 10 Gy, commonly considered unsafe or even dangerous, 206 CIEDs (143 PMs and 63 ICDs) from three different centers, with at least 4 months to Elective Replacement Indicator (E.R.I.) were observed.Methods:All CIEDs had a baseline telemetry interrogation. Single chamber devices were programmed in the VVI/40 mode and dual or triple chamber devices were programmed in the DDD/40 mode. Rate adaptive function was disabled. In ICDs, antitachycardia therapies were disabled with the ventricular tachycardia/fibrillation detection windows left enabled. Prior to exposure, a centering CT was performed to build the corresponding treatment plan and CIEDs were blinded randomized to either 2, 5 or 10 Gy direct exposure by a low photon-energy LINAC (6MV) in a home-maid water phantom. An in-vivo dosimetry assessed the effective dose received by the CIEDs. All CIEDs were interrogated immediately after exposure.Results:Immediately after RT exposure, 1 reset to emergency mode was observed in a PM (0?5% overall; 0?7% among PMs), while 7 PMs reached the E.R.I immediately after exposure (3?4% overall; 4?9% among PMs) despite sufficient baseline battery charge. 16 ICDs (7?8% overall; 25?4% among ICDs) reporded ventricular tackycardia/fibrillation detections stored in the device memory. All reported events occurred regardless of either 2, 5, or 10 Gy direct exposure. Malfunctions were observed in only older CIEDs.Conclusions:Recent CIEDs withstood direct oncologic RT exposure up to 10 Gy, commonly considered not recommended or even unsafe by manufacturer statements and clinical guidelines. Malfunctions occurred only in older devices.