Short-term effect of low atrial septum pacing on new-onset atrial fibrillation in patients with sinus node dysfunction a prospective randomized single-center study

Abstract

Background: Patients with sinus node dysfunction (SND) are at risk of atrial fibrillation (AF) after dual-chamber pacemaker implantation. AF is a risk factor for cardiovascular and cerebrovascular events. The location of atrial electrodes can influence AF occurrence. This study aimed to investigate the differences in the incidence of new-onset AF between low atrial septal (LAS) and right atrial appendage (RAA) pacing in patients with SND and explore the possible underlying mechanisms.

Materials and methods: We included 155 patients with SND, including 83 and 72 who received LAS and RAA pacing, respectively. We collected baseline data, electrocardiogram indexes, and ultrasound cardiogram indexes, as well as postoperative complications, program testing data of the pacemaker, electrocardiogram indexes, and AF occurrence during 1-year follow-up.

Results: The operative duration was significantly longer in the LAS group than in the RAA group (P < 0.001). The intraoperative P-wave amplitude was significantly smaller in the LAS group than in the RAA group (P =0.001). The P-wave duration and cumulative percentages of ventricular pacing (Cum % VP) in the LAS group were significantly lower than those in the RAA group (P < 0.001 and P =0.039, respectively). At 1-year follow-up, the incidence of new-onset AF was significantly lower in the LAS group than in the RAA group (16.9% vs. 36.1%, hazard ratio [HR]: 0.363, 95% confidence interval [CI]: 0.156-0.846, P = 0.019). The independent risk factors for new-onset AF at 1-year follow-up were combined bundle branch block (odds ratio [OR] 8.015, 95% CI 1.232-52.132, P = 0.029), large left atrium (OR 5.812, 95% CI 1.202-28.088, P= 0.029), and prolonged postoperative P-wave duration (OR 1.027, 95% CI 1.009-1.045, P = 0.018). LAS pacing was associated with a reduced risk of postoperative AF occurrence (OR 0.072, 95% CI 0.010-0.542, P = 0.011).

Conclusion: For patients with SND after dual-chamber pacemaker implantation, AF incidence within 1 year after LAS pacing was significantly lower than that after RAA pacing. LAS pacing could shorten the postoperative P-wave duration, an independent risk factor for new-onset AF, and LAS pacing effectively reduced the Cum % VP, which may be the underlying mechanism by which LAS pacing prevents postoperative AF occurrence.

Keywords: P-wave duration; atrial fibrillation; low atrial septal pacing; right atrial appendage pacing; sinus node dysfunction.

Figure 1.

LAS and RAA pacing sites. The red square represents the pacing site of the LAS, and the green ellipse represents the pacing site of the RAA. Abbreviations: LAS pacing, low atrial septal pacing; RAA pacing, right atrial appendage pacing

Figure 2.

X-ray images of LAS and RAA pacing. Abbreviations: LAS pacing, low atrial septal pacing; RAA pacing, right atrial appendage pacing.

Figure 3.

Flowchart of the study procedure. After enrollment, each patient was randomly assigned to receive either LAS or RAA pacing. The ambulatory data were collected at each follow-up visit. Abbreviations: AF, atrial fibrillation; COPD, chronic obstructive pulmonary disease; CKD, chronic kidney disease; LAS pacing, low atrial septal pacing; RAA pacing, right atrial appendage pacing; PAH, pulmonary arterial hypertension; SHD, structural heart disease; SND, sinus node dysfunction.

Figure 4.

Cumulative incidence of postoperative new-onset AF during the 1-year follow-up period

Figure 5.

Forest plot showing multivariate binary logistic regression results for postoperative new-onset AF.