Effectiveness and safety of atrioventricular node ablation after his bundle pacing in patients with uncontrolled atrial arrhythmias: long-term results analysis

Abstract Introduction In the evolving treatment of atrial fibrillation (AF), atrioventricular (AV) node ablation is being reconsidered as an early option for patients with inadequate AF control and limited cure potential. Although interest in physiological pacing is growing, concerns about the long-term safety of permanent His bundle pacing (p-HBP) persist. Our current study aims to evaluate the long-term outcomes of patients who underwent AV node ablation and p-HBP, focusing on left ventricular ejection fraction (LVEF), NYHA class, readmissions, and pacing parameters. Methods This descriptive observational study involved patients with uncontrolled permanent atrial arrhythmias who were eligible for heart rate control (between January 2019 and July 2020) and underwent p-HBP and AV node ablation, followed by a near four-year follow-up period. Results We conducted a long-term follow-up study with a median duration of 47 months (21–56 months) on 36 patients who received (p-HBP) followed by AV node ablation. The average age was 77 years (range, 70–81 years), predominantly female (69.4%), with a high prevalence of hypertension (91.7%). The main indications for ablation were uncontrolled atrial fibrillation (58.4%) and atypical atrial flutter (33.3%), (Table 1). At baseline, the median left ventricular ejection fraction (LVEF) was 55% (45–60%). Notably, LVEF improved significantly from 35% to 50% in those with reduced baseline function (p<0.05). NYHA class improvements were also observed over time, (Table 2). His thresholds remained stable being 1.25 V at 0.4 ms (0.95–2 V at 0.4 ms) before AV node ablation and 1.45 V at 0.4 ms (0.75–2.5 V at 0.4 ms), p=0.93, at long-term follow-up. The impedances remained stable as well and no complications related to the pacemaker occurred. Although after the ablation 80% of the patients had ventricular escape, in subsequent follow-up visits, only 45% presented escape above 30 bpm during consultations, with R wave signal 1.4 mV (0.5-6.25). During the follow-up, there were no observed complications associated with the pacemaker or lead dislodgments. Medication for heart rate control significantly decreased from 1.5 to 0.32 (p<0.05), while hospital admissions for tachyarrhythmias dropped markedly. Three deaths were noted during follow-up, attributed to heart failure and cancer, but conclusions regarding mortality are limited by the small sample size. Conclusions AV node ablation and His bundle pacing (p-HBP) significantly improve functional class and LVEF, with benefits mantained over time. Patients experience fewer emergency visits and reduced heart rate medication. Pacing parameters remain stable long-term follow-up.