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The indications for cardiovascular implantable electronic devices (CIEDs) including defibrillators and pacemakers, are increasing, as is the cancer burden for older patients. Recommandations have been published, but the interactions between CIEDs and ionising radiations are insufficiently known by radiotherapy medical teams and cardiology teams. The production of secondary neutrons by the use of high energy beams (superior to 10MV). Telecardiology is a major asset for the monitoring of these patients. The objective of this study, is to analyze the radiotherapy related CIEDs dysfunctions (reversion of the device to back-up mode) in a cohort of patients followed by remote monitoring of their device in the Lille University Hospital.

In 2009, at Lille University Hospital, a single-center register was designed to prospectively analyze the alerts form remote monitoring of CIEDs, regardless of the device manufacturer. All the alerts received through these remote monitoring systems were included in the register, and were classified as clinical or technical alerts. Technical alerts included lead-related alerts and device-related alerts. Clinical alerts included arrhythmias and heart failure-related alerts. For the purpose of the present study, the technical device-related alerts arising from reversion to back-up mode were extracted from the register, and their cause was described and analyzed.

2745 patients were enrolled over a mean follow-up of 3.5 years.  Among 89,806 event-triggered transmissions, 17,505 were classified as technical alerts. Only 20 alerts were related to reversion to back-up mode, with 8 of them caused by radiotherapy in 7 patients. None of these alerts was followed by a clinical adverse event before the CIEDs problem was resolved. For 8 of these alerts, 7 had their CIEDs out of field. All patients were treated with high Energy X-Rays, ranging from 18 to 25MV. For the patient with in field CIED, the dose to the device was less than 0,3Gy. The localisations of the radiotherapy were : Pelvic (5 patients), Encephalic (1 patient), controlateral lung apex (1 patient).

All the alerts involving CIEDs and radiotherapy in this population were associated with high energy X-rays. Radiation oncologist should avoid using X-rays with an energy superior to 10MV when treating patients with CIEDs, even if the device is far from the field.