Prevention of Ventricular Desynchronization by Permanent Para-Hisian Pacing After Atrioventricular Node Ablation in Chronic Atrial Fibrillation. A Crossover, Blinded, Randomized Study Versus Apical Right Ventricular Pacing

Objectives: The aim of our study was to evaluate the feasibility, the safety, and hemodynamic improvements induced by permanent para-Hisian pacing in patients with chronic atrial fibrillation and narrow QRS who underwent atrioventricular (AV) node ablation. Background: Right ventricular apical pacing, inducing asynchronous ventricular contraction, may impair cardiac function; permanent para-Hisian pacing could preserve interventricular synchrony and improve left ventricular function. Methods: After AV node ablation, 16 patients were implanted with a dual-chamber pacemaker connected to a screw-in lead positioned in close proximity to the His bundle and to a right ventricular apical lead. Clinical and echocardiographic data were collected at baseline and after two randomized six-month periods (with para-Hisian and conventional pacing). Results: During para-Hisian pacing, the interventricular electromechanical delay improved as well (34 ± 18 ms) as during right apical pacing (47 ± 19 ms), p < 0.05. Para-Hisian pacing allowed an improvement in New York Heart Association functional class (1.75 ± 0.4 vs. 2.33 ± 0.6 at baseline and 2.5 ± 0.4 during apical pacing, p < 0.05 for both), in quality-of-life score (16.2 ± 8.7 vs. 32.5 ± 15.0 at baseline, p < 0.05), and in the 6-min walk test (431 ± 73 m vs. 378 ± 60 m at baseline and 360 ± 71 m during apical pacing, p < 0.5 for both). Mitral and tricuspid regurgitation improved during para-Hisian pacing (1.22 ± 0.8 and 1.46 ± 0.5 index, respectively, vs. 1.68 ± 0.6 [p < 0.05] and 1.62 ± 0.7 [p = NS] index at baseline, respectively), with a slight worsening during apical pacing (1.93 ± 1 and 1.93 ± 0.7 index, respectively, p < 0.05 for both). Conclusions: Permanent para-Hisian pacing is feasible and safe. Compared with conventional right apical pacing, it allows an improvement in functional and hemodynamic parameters over long-term follow-up.