Safety of Contemporary Radiation Therapy in Patients With Cardiac Implantable Electronic Devices: Implications for...

Radiation therapy (RT) can cause cardiac implantable electronic device (CIED) malfunction, primarily reset. Given changes in RT and CIED technologies, large observational studies examining malfunction of contemporary CIEDs during modern-day RT are needed to guide clinical practice.

Electronic medical records of all consecutive patients with CIEDs who underwent RT at a large tertiary cancer center between January 2015 and January 2022 were reviewed. All patients had CIED interrogation before and after completion of RT. Device-related data and RT-specific variables were collected. Statistical analyses were performed at the RT course level.

Over a period of 7 years, 677 patients (median age, 74 [interquartile range, 67. 8-79.2] years; 72% men) with CIEDs (498 [66%] pacemakers and 254 [34%] implantable cardioverter-defibrillators) underwent 752 courses of RT (photon, 83.5%; proton, 10.5%; electron, 6%). Only 9 patients (1.3%) underwent CIED relocation before RT. Device malfunction was observed during 8 RT courses (1.1%), primarily soft reset with data loss. All device malfunctions were observed with neutron-producing radiation (proton and photon >10 MV). CIED type (pacemaker or implantable cardioverter-defibrillator), magnetic resonance imaging conditional or nonconditional system, and radiation site (thorax or nonthorax) did not show statistical differences between RT courses with reset versus no reset. No transient signal interference or oversensing due to RT was recognized by the CIED.

CIED malfunction is a rare complication of contemporary RT, occurring primarily with neutron-producing radiation, most of CIED malfunction cases are without serious clinical consequences. Transient signal interference and oversensing during RT does not appear to be a clinical concern in contemporary CIEDs.