Leadless pacemakers are unaffected by external beam radiation in a phantom model

Radiation therapy has the potential to interfere with the function of implanted pacemakers. However, both pacemakers and radiation therapy have undergone significant advancements over the last decade, with the introduction of leadless pacemakers, high-energy photon beams, and flattening filter-free (FFF) radiation modes.

Our study aims to assess the effects of radiation exposure on leadless pacemakers (Micra VR, Medtronic) at various dose rates using the Varian TrueBeam and Ethos systems.

5 pacemakers were exposed to radiation at dose rates ranging from 43 cGy/min to 147 cGy/min using 6MV, 6FFF, 10MV, 10FFF, and Ethos 6FFF energy beams, simulating clinical radiation therapy conditions. Devices were submerged in half saline and placed adjacent to the radiation field, and their sensing channels were monitored in real-time. We sought to evaluate the behavior of the pacemakers in both ventricular pacing and sensing and no pacing, ventricular sensing, and no response to sensing modes, analyzing noise amplitude, pacemaker output, and overall device performance during and after irradiation.

Pacemakers in both ventricular pacing and sensing and no pacing, ventricular sensing, and no response to sensing modes maintained stable performance across all energy settings (6MV, 6FFF, 10MV, 10FFF, and Ethos 6FFF) with no significant changes in output or sensing behavior, even at higher dose rates. A slight increase in noise amplitude was observed at 6FFF, but device function remained unaffected. No electromagnetic interference was detected.

The Micra VR leadless pacemaker can withstand various radiation dose exposures commonly encountered in clinical radiotherapy without malfunctioning.