Author(s)

John Ip¹, Abdul R. Safadi¹, Randy Ip¹, Matthew Gaskill¹, Rajesh Banker², Derek Exner³, Srinivas Dukkipati⁴, Mayer Rashtian⁵, Imran Niazi⁶

¹Cardiac Electrophysiology Department, Michigan State University, Lansing, USA.
²Cardiac Electrophysiology Department, Premier Cardiology, Inc, Newport Beach, USA.
³Cardiac Electrophysiology Department, Foothills Medical Centre, Calgary, Canada.
⁴Cardiac Electrophysiology Department, Mount Sinai Hospital, New York, USA.
⁵Cardiac Electrophysiology Department, Huntington Memorial Hospital, Pasadena, USA.
⁶Cardiac Electrophysiology Department, Aurora Medical Group, Milwaukee, USA.

Background: The Nanostim {trade mark, serif} Leadless Cardiac Pacemaker (LCP) has been shown to be safe and effective in human clinical trials. Since there is little information on the effect of implant location on LCP performance, the aim of this study was to determine whether anatomic position affects the long-term pacing performance of the LCP. Methods: Patients who enrolled in the Leadless II IDE Clinical Trial and had finished 6 months follow up (n = 479) were selected for the study. The implanting investigators determined the LCP final position under fluoroscope, which was categorized into three groups: RV apex (RVA, n = 174), RV apical septum (RVAS, n = 101), and RV septum (RVS, n = 204) (Figure 1). Data on capture threshold (at a 0.4 ms pulse width), R-wave amplitude and impedance were analyzed at implant, hospital discharge and 2 weeks, 6 weeks, 3 months and 6 months post-implant. Results: At implant, the mean capture thresholds in the RVA, RVAS and RVS were 0.77 ± 0.45, 0.81 ± 0.61 and 0.78 ± 0.59 volts, respectively. R-wave amplitudes were 8.0 ± 3.0 mV, 7.7 ± 2.9 mV and 7.6 ± 2.9 mV, respectively. Impedance values were 727 ± 311, 765 ± 333, and 677 ± 227 respectively. There were no differences among the 3 implant locations in capture threshold or R-wave amplitudes at 6 months (P > 0.06); however, all 3 performance parameters significantly improved over time (P < 0.001). Conclusions: The LCP implant location does not affect capture thresholds or R-wave amplitudes at 6 months, and there is little effect on impedance. Although implant location does not appear to be a predictor of electrical performance, additional long-term data will help guide optimal implant location.

Pacing Lead Location, Leadless Pacing, Lead Impedance, Pacing Threshold, R-Wave Amplitude

Ip, J. , Safadi, A. , Ip, R. , Gaskill, M. , Banker, R. , Exner, D. , Dukkipati, S. , Rashtian, M. and Niazi, I. (2017) Leadless Cardiac Pacemaker: Does Anatomical Position at Implant Affect Long-Term Electrical Performance?. Journal of Biomedical Science and Engineering, 10, 500-508. doi: 10.4236/jbise.2017.1011038.