Bridging Implantable Cardioverter-Defibrillator Patients Undergoing Radiotherapy with a Wearable Cardioverter-Defibrillator

Abstract

Background: Chest radiation therapy (RT) in patients with an implantable cardioverter defibrillator (ICD) can be problematic and cause transitory malfunction or permanent damage to the device. If the ICD cannot be properly shielded from the radiation necessary for the treatment, then it may be necessary to turn off certain aspects (i.e. tachy-therapy) of the device or to temporarily remove the device leaving the patient without protection and exposing to high risk of complications. The wearable cardioverter defibrillator (WCD) is guideline recommended as bridging therapy in patients requiring temporary removal or inactivation of an ICD. Objectives: The objective of this analysis was to assess the wearable cardioverter defibrillator as a tool in high-risk implantable cardioverter defibrillator patients with cancer during the weeks to months of radiation therapy. Methods: Two retrospective cohorts were analyzed from the University of Padova (Italy) and from the manufacturer’s US registry. Patients undergoing RT who had their ICD removed or deactivated and were prescribed a WCD were included. Demographic, medical history and device usage data collected. Results: Eighty patients were analyzed (76 US, 4 Padova). The median age was 69 years and 56% were female. The most common cancer types were breast (44%) and lung (33%). Median wear time of the WCD was 22.2 hours/day over 57 days. Strategies to protect ICDs from RT involved either removing the device (82.5%) or turning off therapy in the remaining 14 (17.5%). Ventricular arrhythmias (VA) were recorded by the wearable cardioverter defibrillator in four patients, with two sustained episodes in a patient that were successfully cardioverter by the wearable cardioverter defibrillator, and three patients with non-sustained ventricular arrhythmias that did not receive shocks. Five deaths occurred four with an asystole event and one while not wearing the device. Conclusions: This study supports a role for the wearable cardioverter defibrillator in protecting implantable cardioverter defibrillator patients while undergoing radiation therapy. Back-up pacing considered for patients at risk of Bradyarrhythmias.