Atrial pacing minimization in sinus node dysfunction and risk of incident atrial fibrillation: a randomized trial

Abstract

Background and Aims High percentages of atrial pacing have been associated with an increased risk of atrial fibrillation. This study is aimed at evaluating whether atrial pacing minimization in patients with sinus node dysfunction reduces the incidence of atrial fibrillation. Methods In a nationwide, randomized controlled trial, 540 patients with sinus node dysfunction and an indication for first pacemaker implantation were assigned to pacing programmed to a base rate of 60 bpm and rate-adaptive pacing (DDDR-60) or pacing programmed to a base rate of 40 bpm without rate-adaptive pacing (DDD-40). Patients were followed on remote monitoring for 2 years. The primary endpoint was time to first episode of atrial fibrillation longer than 6 min. Secondary endpoints included longer episodes of atrial fibrillation, and the safety endpoint comprised a composite of syncope or presyncope. Results The median percentage of atrial pacing was 1% in patients assigned to DDD-40 and 49% in patients assigned to DDDR-60. The primary endpoint occurred in 124 patients (46%) in each treatment group (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.76–1.25, P = .83). There were no between-group differences in atrial fibrillation exceeding 6 or 24 h, persistent atrial fibrillation, or cardioversions for atrial fibrillation. The incidence of syncope or presyncope was higher in patients assigned to DDD-40 (HR 1.71, 95% CI 1.13–2.59, P = .01). Conclusions Atrial pacing minimization in patients with sinus node dysfunction does not reduce the incidence of atrial fibrillation. Programming a base rate of 40 bpm without rate-adaptive pacing is associated with an increased risk of syncope or presyncope.

Atrial Pacing Negatively Affects Left Atrial Morphological and Functional Parameters Similarly to Atrioventricular Dyssynchrony

“…The changes were noted as early as the one-month follow-up visit and were maintained during the study. Recently published data from the Danpace II trial [ 25 ] have supported a higher base rate of atrial pacing based on clinical expression of symptoms; however, the influence of atrial pacing on structural and functional changes in atria, which can have a late impact on progression of disease, were not evaluated.…”

“…Considering AV timing optimization not just to avoid RV pacing but also to correct for interatrial dyssynchrony might further help to preserve LA function [ 12 , 16 , 31 ]. Avoiding apical RV pacing during implantation [ 25 ] and reducing LV dyssynchrony could also help to maintain LV function [ 28 , 29 ]. Conduction system pacing, aiming to benefit from the heart’s intrinsic conduction system, can possibly maintain interventricular synchrony and LV filling pressure.…”