96-39: Newly diagnosed atrial fibrillation after dual chamber pacemakers implantation: the importance of right ventricle pacing site

Abstract

Background: Preserving atrioventricular synchrony as been accepted as an important benefit of atrial and dual-chamber (DDD) pacing. However, little is known about the incidence of atrial fibrillation (AF) and AF burden after DDD implantation, and what is the relation of AF occurrence with the right ventricle (RV) pacing site. Purpose: This study assessed the incidence of newly AF episodes after DDD pacemaker implantation and analyzed the its correlation with lead location in RV. Methods: from 2011 to 2015, a total of 657 consecutive DDD pacemaker patients (P) (age 73.1 ± 10.7 years; male 59.7%) with AV block or sick sinus syndrome, with no prior history of AF, were followed for a mean of 20.9 ± 16.7 months. Occurrence of AF (“automatic mode switch” episodes with documented AF), total AF burden and cumulative atrial and RV pacing % were investigated for both pacing sites: RV apex (RVap) and septal (RVsp) sites. Results: RV pacing leads were located in the RVap and RVsp positions in 56.2% and 43.8%, respectively. Newly occurrence of AF was observed in 171P (26.0%) during the follow-up period. Mean time to 1st AF episode since implantation was 16.8 ± 12.7 months and in 62.2% of the cases it lasted ≥1h. Compared to non-AF P, those with AF had similar age (73.9 ± 9.96 vs. 72.8 ± 10.9 years, p = ns), % of RV pacing (64.9 ± 39.0% vs. 58.7 ± 44.3%, p = ns) and % of atrial pacing (53.4 ± 33.5% vs. 49.9 ± 42.7%, p = ns). P with lead position in RVsp site presented similar % of RV pacing (58.8 ± 43.0% vs. 58.4 ± 44.0%, p = ns) and % of atrial pacing (51.6 ± 40.3% vs. 49.1 ± 39.8%, p = ns), with a lower incidence of AF (16.2% vs. 32.9%, p < 0.001). Multivariable Cox-regression analysis revealed that a RVap lead position (HR = 0.431; 95% CI 0.28-0.77;p <0.0001) and RVap pacing <50% (HR = 1.55; 95% CI 1.03-2.34;p 0.035) were independent predictors for newly occurrence of AF. Conclusions: Newly occurrence of AF is a frequent finding after DDD pacemaker implantation. RVap lead position and RVap pacing >50% were strongly associated with AF episodes. Regarding the recognized clinical impact of AF, careful RV lead location and device algorithms for minimization of RV pacing should be taken into consideration.