Abstract 14310: Evaluation of Ventricular Pacing Suppression Algorithmsin Dual Chamber Pacemaker: Results of 'Leader' Study

Abstract

Introduction: Several algorithms have been proposed to reduce unnecessary right ventricular (RV) pacing, and their operations are based on two different mechanisms: (i) atrioventricular (AV) hysteresis (AVH) and (ii) DDD to AAI pacing mode change. Hypothesis: The purpose of our study was to evaluate the efficacy and safety of two ventricular pacing suppression algorithms: Intrinsic Rhythm Support (IRS) plus algorithm (using AVH, IRSplus) and VP suppression (DDD to AAI mode change) algorithm (VpS). Methods: This was a multicenter, randomized study conducted in 11 tertiary hospitals in South Korea. Patients with sinus node dysfunction and receiving dual-chamber permanent pacemaker implantation were included in this study. After the implantation, patients maintained a fixed AV interval for three months. The AV conduction time was determined as the "atrial pacing to ventricular sensing interval" observed from the marker channel during the PPM implantation was set as the sensed AV delay. The paced AV delay was set to be the sensed AV delay+30ms. Subsequently, patients were randomly assigned to either the VpS or IRSplus algorithm group and were followed for 12 months with assessments every 6 months. Results: A total of 118 patients were enrolled, and the total RV pacing percentage (Vp%) of the patients during the 3 months with a fixed AV interval was 10.9±16.0 on average. They were randomly assigned to VpS and IRSplus groups, with 62 and 56 patients in each group. Six months later, the average Vp% was 14.6±18.8 to 2.7±6.0, P<0.001 and 6.8±10.9 to 1.1±4.0, P<0.001 for the VpS and IRSplus groups, respectively. This trend was maintained for additional 6 months (VpS group: 4.6±9.5; IRSplus group: 1.2±3.8). The effects of algorithms were more pronounced in groups with an intrinsic PR interval of < 200ms, and the IRSplus showed better efficacy (Figure). Conclusions: The two ventricular pacing suppression algorithms were effective in reducing Vp% compared to the fixed AV interval.