Chronic performance of a leadless cardiac pacemaker: 1-year follow-up of the LEADLESS trial

Background A leadless cardiac pacemaker (LCP) system was recently introduced to overcome lead-related complications of conventional pacing systems. To date, long-term results of an LCP system are unknown. Objectives The aim of this study was to assess the complication incidence, electrical performance, and rate response characteristics within the first year of follow-up of patients implanted with an LCP. Methods We retrospectively assessed intermediate-term follow-up data for 31 of 33 patients from the LEADLESS trial cohort who had an indication for single-chamber pacing and received an LCP between December 2012 and April 2013. Results The mean age of the cohort was 76 ± 8 years, and 65% were male. Between 3 and 12 months of follow-up, there were no pacemaker-related adverse events reported. The pacing performance results at 6- and 12-month follow-up were, respectively, as follows: mean pacing threshold (at a 0.4-ms pulse width), 0.40 ± 0.26 V and 0.43 ± 0.30 V; R-wave amplitude 10.6 ± 2.6 mV and 10.3 ± 2.2 mV; and impedance 625 ± 205 Ω and 627 ± 209 Ω. At the 12-month follow-up in 61% of the patients (n = 19 of 31), the rate response sensor was activated, and an adequate rate response was observed in all patients. Conclusions The LCP demonstrates very stable performance and reassuring safety results during intermediate-term follow-up. These results support the use of the LCP as a promising alternative to conventional pacemaker systems. Continued evaluation is warranted to further characterize this system.