An analysis revealed that in a cohort of patients with cardiovascular implantable electronic devices (CIEDs) requiring radiotherapy (RT), all cases of single-event upset malfunction (device memory data loss or parameter reset) was 21% for neutron-producing RT and 0% for non-neutron- producing RT (178 courses).

Whenever feasible, the use on non-neutron-producing radiotherapy is recommended, according to a retrospective review published online ahead of print in JAMA Oncology.

Researchers included all patients with a functioning CIED who underwent RT between August 2005 and January 2014 with CIED interrogation data following RT in an academic cancer center.

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The intent was to find clinical incidence, predict malfunction, and describe associated clinical consequences in a large cohort of patients treated with photon- and electron-based RT.

A total of 249 courses of photon- and electron-based RT were found in 215 patients (123 [57%] pacemakers; 92 implantable cardioverter defibrillators [43%]). Substantial neutron production was generated in 71 courses (29%).

Malfunction of CIED, characterized by single-event upset and delayed effects including signal interference, pacing threshold changes, and premature battery depletion that was attributed to RT occurred during 18 courses (7%). 

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Those most likely to have a single-event upset were patients treated to the abdomen/pelvis region. Neutron-producing radiation (>10 MV) was the principal risk factor for device malfunction.

Six patients with a CIED parameter reset developed clinical symptoms: 3 hypotension and/or bradycardia, 2 abnormal chest ticking consistent with pacemaker syndrome, 1 congestive heart failure. The 3 episodes of signal interference did not result in clinical effects. No delayed malfunctions were directly linked to RT.


  1. Grant JD, Jensen GL, Tang C, et al. Radiotherapy-induced malfunction in contemporary cardiovascular implantable electronic devices: clinical incidence and predictors. JAMA Oncol. 2015. [epub ahead of print]. doi: 10.1001/jamaoncol.2015.1787.