Long-term time-course of atrial sensing and incidence of atrial fibrillation in patients with VDD versus DDD pacemakers

Abstract

Abstract Introduction VDD pacemakers (PM) theoretically have the same advantages with respect to maintaining atrioventricular (AV) synchrony as dual-chamber (DDD) pacemakers, with lower costs and simpler implantation procedure. However, their use is often limited by concerns about the maintenance of atrial sensing (AS) and the occurrence of atrial fibrillation (AF). Purpose We aimed to compare long-term atrial sensing stability, the incidence of AF and complications in VDD and DDD systems. Methods We retrospectively enrolled patients who underwent VDD or DDD PM implantation for AV block between 2014 and 2021 from 2 centers. Clinical, analytical and electrical variables at implantation, their evolution and events at follow-up (25.2±16.2 months) were collected, comparing the groups by Kaplan-Meier and Cox multivariate analysis. Results 487 patients who underwent PM implantation were included, 189 (38,8%) received a VDD PM and 298 (61,2%) a DDD PM. Patients with VDD were older and had a higher prevalence of risk factors and lower atrial voltage at implantation (Table). Complications at implantation and early complications were scarce and without significant differences in both groups. During follow-up, there was a reduction in atrial voltage in the VDD group (implant 1.4+0.8 mV; follow-up 1.2+0.9 mV; p<0.01), with stability in the DDD group (3.8+2.1 vs 3.9+2.2 mV). Total percentages of AS loss were 23.2% (VDD) vs 2.3% (DDD); p<0.01) (Figure 1). In the Cox multivariate analysis the risk of late AS loss was higher in the VDD group (HR=7.6; 95% CI 2.86-20.3; p<0.001) together with the AS values at implant (HR=0.72; 95% CI 0.52-1.00; p=0.052). AS loss was corrected with reprogramming in 23 patients, reintervention was needed in 1 (2%) and VVI was abandoned in 27 (53%). The risk of AF occurrence was lower in the VDD group (HR=0.39 CI 95% 0.18-0.87; p=0.021) (Figure 2). Conclusions In the long term, AS is significantly reduced in VDD MPs, leading to its loss in a quarter of VDD patients. It is usually correctable with reprogramming, rarely requiring abandonment to VVI. AS at implantation is crucial as it is directed related to the AS during follow-up. DDD PMs were independently associated with a higher incidence of AF, with no differences in the remaining complications.TableFigure