New generation implantable cardiac rhythm devices allow safe radiotherapy treatments: A large single centre study

INTRODUCTION: Many patients requiring radiotherapy for malignancies have an already implanted cardiac rhythm device. Previous studies reported a variety of device dysfunctions related to high dose radiation. Aim of this study was to assess the impact of current optimal radiotherapy treatment guided by computed tomography on current generation implantable devices. METHODS: Consecutive patients with implanted pacemakers (PMK) and implantable cardioverter defibrillators (ICD) referred for radiotherapy treatment in any district were enrolled at our Centre and followed prospectively with device interrogation before and just after each radiotherapy cycle. A magnet was positioned on the device in patients with implanted defibrillators or pacemaker-dependency. RESULTS: Overall, 48 patients (74.8 years (9.3), 39 males (81.3)) with implantable devices underwent radiotherapy (29 pacemakers and 19 ICDs). Interval between device implant and start of radiation therapy was 2.9 (1.6) years. Radiotherapy was performed under computed tomography guidance, and a mean of 73.5 (45.0) Gy were administered with a mean of 24.8 (14.6) fractionated doses. About half of the patients underwent thoracic radiotherapy, and 9 were treated for a left thoracic malignancy ipsilateral to the implanted device. No device failures were observed at post-treatment device interrogation, nor changes in electrical parameters, inappropriate shocks, device reprogramming or memory reset. None of the patients experienced premature battery failure or other unexpected anomalous findings at the end of the radiation therapy cycle. CONCLUSION: Radiation therapy for malignancies is safe among patients with implanted current generation cardiac rhythm devices.