Radiation Therapy-Induced Dysfunction in Cardiovascular Implantable Electronic Devices.

PURPOSE

The prevalence of patients with cardiovascular implantable electronic devices (CIEDs) who receive radiation treatment for cancer is increasing. External beam radiation therapy (RT) can affect the electronic components. This study aimed to evaluate the incidence and predictors of new onset CIED dysfunction in patients treated with RT.

METHODS AND MATERIALS

We retrospectively analyzed data from 230 patients with CIEDs who received radiation treatment at the Radiation Oncology Center of CHU de Québec - Université Laval between February 2007 and November 2013. The reviewed data included baseline characteristics, CIEDs, and RT treatment specifications. Patients with CIEDs were analyzed before, during, and at the end of radiation treatment. High- and low-energy photon or electron beam radiation from linear accelerators, orthovoltage machines, and high-dose rate brachytherapy delivery were used. Abnormal events could be one of the following: total or partial deprogramming of the CIED parameters, onset of new symptoms, or new arrhythmia.

RESULTS

This study is based on one of the largest cohorts. A total of 18 events in 16 patients (7.8%) were recorded. Of the 18 events, 16 had at least part of the radiation treatment delivered with photo neutrons producing high-energy RT (neutron producing RT). Only 2 abnormal events occurred during non-neutron producing RT. Both the prescription dose and the dose estimated at the location of the pacemaker were correlated with the probability of an abnormal event (P = .0006 and P = .003, respectively). Among the 16 patients, clinical symptoms were noted in only 1 patient (6.3%).

CONCLUSIONS

CIED malfunctions are relatively uncommon and do not seem to be life threatening. We recommend limiting the dose at the CIED and avoid neutron-producing RT to reduce the risk of CIED malfunction.