Effect of pacing the right ventricular mid-septum tract in patients with permanent atrial fibrillation and low ejection fraction.

Introduction: Permanent right ventricular (RV) pacing leads have been traditionally implanted in the right ventricular apex (RVA). Nowadays, some deleterious effects of RVA pacing have been recognized. The aim of this study was to evaluate the effect of different sites of RV pacing in patients with permanent atrial fibrillation (AF) and low ejection fraction (LEF) needing a pacemaker (PM) implantation.
Methods: Two hundred seventy-three patients with permanent AF and EF <30% underwent a one-chamber rate responsive (VVIR) PM implant procedure. Patients were divided into two groups: Group A, including 113 patients with the pacing lead tip placed in the RV mid-septum, and Group B of 120 patients with the pacing lead tip placed at the apex of RV. All patients had clinical and Echo control after 1, 3, 6, 12, and 18 months after PM implantation to assess New York Heart Association (NYHA) class and EF.
Results: After 18 months, NYHA class changed in Group A from 2.9 +/- 0.4 at implant to 1.7 +/- 0.3 at 18 months (P = 0.01), and in Group B from 3.0 +/- 0.5 at implant to 3.3 +/- 0.6 at 18 months (P = n.s.). EF increased in Group A: 28 +/- 2% at implant, 33 +/- 1% at 18 months (P = 0.0125), while no significant changes were observed in Group B: at implant 27 +/- 2%, 26 +/- 2% at 18 months (P = n.s.).
Conclusion: The present study suggests that more physiological pacing from the RV sept can improve EF and quality of life (QoL) in patients with permanent AF and low EF needing a PM.