LEAD INTEGRITY ALERT IS USEFUL FOR PERFORMANCE ASSESSMENT OF BIOTRONIK LINOX LEADS

Abstract

BACKGROUND: Patients with PMs or ICDs may be exposed to significant electromagnetic fields (EMF) from high voltage transmission lines (HVTL), which may interact with their device. To our knowledge, the rate of electromagnetic interference (EMI) has not been quantified nor have the circumstances of these EMIs. These were the objectives of the current registry. METHOD: Between February 2012 and March 2014, 18 296 device interrogations from patient visits to the PM/ICD clinic were reviewed (11 640 from PMs and 6 656 from ICDs). Fifty patients were recruited after noise episodes were seen during a routine follow-up interrogation. Only 10% of patients with noise episodes refused recruitment in the registry. Recruited patients were asked to keep a detailed log of their activities and travels. Their devices were then re-interrogated after 1, 4 and 12 weeks. Noise events registered on the devices interrogated in the PM/ICD clinic were correlated with a geographical map of the EMFs created by HVTLs, provided by Hydro-Quebec, the province of Quebec’s hydroelectric producer. RESULTS: Two patients were lost to follow-up. Of the remaining 48, 25 had further interference episodes for a total number of 1,080 episodes. Of these, 985 (91.2%) took place at home, 76 (7.1%), during an unknown activity (no activity recorded in the patient log at the time of the interference) and 19 (1.8%), during travels where a HVTL was identified in the vicinity. All of these travels, but one, were in motor vehicles which acted as a Faraday cage and shielded the patients and device from the electric field generated by the HVTLs. No episode was associated with a movement directly under a HVTL, on foot. There was no difference in the morphology of the noise signals based on the type of activity. A single inappropriate mode switch was noted as a result of the noise episodes. There was no relation between patient reported symptoms and the noise episodes. CONCLUSION: The overall rate of EMI is very low (0.3%) and the majority of episodes occur in the home environment. Despite the large number of patients sampled, there were no episodes of EMI linked to passage under a HVTL, which is reassuring from a public safety standpoint.