Revisiting the Impact of Radiation Therapy on Cardiac Implantable Electronic Device (CIED) Function

Moshe Rav Acha MD, PhD; Ben W. Corn MD

Disclosures

J Cardiovasc Electrophysiol. 2018;29(9):1276-1279. 

In This Article

Abstract and Introduction

Introduction

The study in this issue of the Journal published by Bravo–Jaimes et al is based on a retrospective analysis of a cohort of 109 patients implanted with CIED (Cardiac Implantable Electronic Device) who underwent radiation therapy (RT), exploring device malfunction attributed to RT.[1] The authors have thoroughly evaluated various irradiation parameters that might have had an impact of CIED function, including: RT type (photon/electron beam), energy, sequence, dose and fractionation, RT site (ie, the radiation target area), and its distance from the CIED with calculated estimation of the radiation dose delivered to the CIED.

The study outcomes of RT–related device malfunctions were evaluated by retrospective analysis of patients' charts and device interrogation reports prior to, during and following RT. There were 6/109 (5.5%) patients in whom a repeat device interrogation after RT initiation revealed an apparently new CIED malfunction. All these malfunctions were relatively minor ones including: partial device program resetting leading to loss of historic arrhythmic data, minor changes in right or left ventricular lead thresholds, and some change of right or left ventricular pacing outputs leading to diaphragmatic stimulation in one case and new dyspnea in another case. Notably, some of the above changes were detected approximately 1 month following initiation of RT. In a multivariate analysis, there was no statistical association between any of the radiation parameters evaluated and CIED malfunction. The authors concluded that RT–related CIED malfunction is a relatively rare event resulting in minor device changes without clinical significance, and that these CIED malfunctions could potentially be detected by contemporary remote monitoring systems.

As the authors point out, there are various limitations to the above study. First, the article represents a relatively small single–center study; second, its retrospective nature with the possibility that not all real–time data were evident for the authors; third, the small number of CIED interrogations performed in each case (median = 2), with the possibility that some CIED malfunctions might not have been detected. Moreover, not all cases had a device interrogation prior to RT initiation. Without baseline data, it is not certain that all CIED malfunctions detected within this study were indeed caused by RT.

As RT is being used with increasing frequency, with approximately 50% of all cancer patients receiving RT during the course of their illness,[2] and as radiation technologies are rapidly evolving, it is worth reviewing some basic concepts of this treatment modality that the readership of the Journal interfaces with on a limited basis.

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