Pacing of Left Bundle Branch Area and Atroventricular Node AblatIon in Patients with Symptomatic Atrial Fibrillation

This study aimed to compare the clinical outcomes of left bundle branch area pacing combined with atrioventricular node ablation and pharmacologic treatment optimized according to guidelines in patients with symptomatic atrial fibrillation refractory or intolerant to drug therapy or catheter ablation.

* Multicenter, randomized, open-label clinical trial
* Randomization 1:1 fashion A randomly permuted-block randomization list was generated by computer at a central location and was stratified by center.
* Study duration:

  1. 6 months (for primary outcome)
  2. 24 months (for secondary outcomes)
* Study subjects number: 50 patients (25 patients per group)
* Procedures

  * Atrioventricular node ablation after successful left bundle branch area pacing at the same procedure time.
  * Left bundle branch area pacing will be performed in all patients (using lumenless or stylet-driven lead, on the operator's discretion)
  * Atrioventricular node ablation will be performed using the quadripolar 7-Fr 3.5-mm tip ablation catheter and the use of 8.5-F sheath (SR0 or SL1, St. Jude Medical Inc., St. Paul, MN, USA) depending on the operator's experience, and if not stable or failed, a deflectable sheath (Agilis, Abbott Electrophysiology, Menlo Park, CA, USA) will be used. Repeated ablation procedures will be recommended during follow-up if regression of atrioventricular block has occurred.
  * Immediately after implant, devices were programmed to achieve the shortest QRS duration. Unipolar pacing was initially used to determine left bundle branch capture.

Eligibility Criteria:
Inclusion:

Patients who meet all of the following inclusion criteria 1)-6).

1. Permanent atrial fibrillation
2. Age ≥ 65 years
3. Refractory or intolerant to antiarrhythmic drugs, rate control medications, or catheter ablation
4. New York Heart Association (NYHA) functional class II- IV
5. LVEF \> 40% (within the past 3 months)
6. Patients with at least one of the following:

   1. HF hospitalization (defined as HF as the major reason for hospitalization or treatment for HF lasting ≥12 hours and including treatment with intravenous (IV) diuretics at a healthcare facility) within 12 months
   2. Elevated NT-proBNP (\>900 pg/ml) in the 30 days prior to enrollment

Exclusion:

Patients who meet at least one of the following exclusion criteria 1)-11).

1. Asymptomatic atrial fibrillation
2. Life expectancy to \< 12 months.
3. Primary moderate to severe valvular disease (except for functional mitral valve regurgitation or tricuspid valve regurgitation)
4. Mechanical tricuspid valve replacement
5. Severe chronic kidney disease (estimated Glomerular Filtration Rate ≤ 15 ml/1,73 m2 or receiving renal replacement treatment including hemodialysis or peritoneal dialysis)
6. Obstructive hypertrophic cardiomyopathy
7. Infiltrative cardiomyopathy (amyloidosis, sarcoidosis, Fabry disease, others)
8. Acute coronary syndrome or coronary revascularization (CABG or PCI) \<3 months
9. Severe primary pulmonary disease such as cor pulmonale, irreversible lung disease requiring inhalers, oxygen supplementation
10. Pacemaker/ICD/CRT treatment ongoing, or current pacemaker indication
11. Simultaneous participation in a different randomized clinical trial