The application of fluoroscopic criteria to define leadless pacemakers implant position and the effect of location on device performance.

Abstract

Leadless pacemakers (LPs) were designed to avoid complications associated with transvenous pacing. To minimise risk of perforations, there is preference towards implanting LPs into the septum rather than the apex or free wall.An objective yet feasible way of characterising the LP location is currently lacking. We report a simple radiological method of defining LP position and our analysis of the impact of implantation site on performance of LPs. The first 100 LPs implanted at our UK centre were reviewed and the devices' positions in fluoroscopy images and X-rays based on conventional criteria for lead positions and conventional practice for LPs positioning were assessed. The devices' electrical parameters at implant and at the latest device follow-up were used to compare performance between implantation sites. 35.6% of implants were in the apex. 31.1% in mid-septum, 16.7% in apical septum, 15.5% on the septal right ventricular inflow and 1.1% in the septal RV outflow tract. We had no major complications.Thresholds, R-wave amplitudes, and impedance averaged at 0.67 ± 0.41 V, 10.64 ± 5.30 mV, and 777.67 ± 201.67 Ohms, respectively, at the time of implantation, and 0.66 ± 0.39 V, 14.08 ± 6.14 mV, and 564.29 ± 96.76 Ohms at the last device check. There was no difference in the pacing thresholds or impedance between implant sites. We propose a simple, reproducible way of defining the LP location which can help standardise the assessment of the device location sites across LP implantation centres. Emphasis on the safety and reliability of the leadless pacemakers in a real-world setting.Establishing the variation in the implantation sites for leadless pacemakers and reporting the effect of the implantation sites on the devices' performance.We propose a simple, reproducible way of defining the LP location which can help standardise the assessment of the device location sites across LP implantation centres.