Cardiovascular Implantable Electronic Devices -> Tachycardia Devices: -> Device Technology D-PO06 - Poster Session VI (ID 26) Poster

D-PO06-033 - A Multi-center, Prospective, In-vitro Evaluation Of Cardiac Implantable Devices Ongoing Oncologic Radiotherapy (ID 1349)


Background: Direct photon exposure of cardiac implantable devices (CIEDs), both pacemakers (PMs) or implantable cardioverter-defibrillators (ICDs), during oncologic radiotherapy (RT) courses can impair device function.
Objective: To evaluate potential CIED malfunctions by direct exposure to doses up to 10 Gy in 6-MV oncologic RT, commonly considered unsafe or even potentially harmful, 145 PMs and 65 ICDs were observed in three different centers.
Methods: All CIEDs had a baseline interrogation and reprogramming to VVI/40 or DDD/40 mode, depending on type and model. Rate-adaptive function was disabled in all the CIEDs, whereas in ICDs, even antitachycardia therapies were disabled with the ventricular tachycardia/fibrillation (VT/VF) windowS left enabled. To build the corresponding treatment plan, a centering computed tomography was performed. CIEDs were blinded randomized to receive either 2-, 5- or 10-Gy direct exposure by a 6-MV linear accelerator (in a water phantom, 600 MU/min). The effective dose received by the CIEDs was assessed by a random in-vivo dosimetry. All CIEDs had a telemetry interrogation immediately after exposure and once monthly during a five-month follow-up.
Results: Immediately after photon exposure, no changes in device parameters or software errors were observed in 209 CIEDs (99·5%). A reset to emergency mode occurred in a PM (0·5% overall; 0·7% among PMs). Seven PMs reached the Elective Replacement Indicator immediately after exposure (3·3% overall; 4·8% among PMs). Sixteen ICDs (7·6% overall; 24·6% among ICDs) had multiple VT/VF detections stored in the device memory. Two PMs (1% overall; 1·4% among PMs) reported atrial fibrillation detections. During a four-month follow-up, a non-reprogrammable software reset was reported in one PM three months after a single exposure of 2 Gy (0·5% overall; 0·7% among PMs). Abnormal battery drain was observed in 11 PMs (5·2% overall; 7·6% among PMs), and in 1 ICD (0·5% overall; 1·5% among ICDs). All events presented regardless of exposure dose of either 2, 5, or 10 Gy.
Conclusion: Last-generation CIEDs withstood direct photon exposure up to 10 Gy, commonly considered not recommended or even unsafe by manufacturer statements and clinical guidelines. Malfunctions occurred solely in less recent devices.