AV Node Ablation for AF in Conduction System Pacing: Key Points

The following are key points to remember from a state-of-the-art review on atrioventricular node ablation (AVNA) for atrial fibrillation (AF) in the era of conduction system pacing:

1. In patients with persistent AF refractory to other treatments, implantation of a permanent pacemaker and AVNA is a reasonable second-line strategy. However, its use has traditionally been limited by an increased risk of heart failure (HF) secondary to ventricular dyssynchrony caused by chronic right ventricular (RV) apical pacing. 
   
   
2. Because the risk of ventricular dyssynchrony may be decreased with conduction system pacing of the His bundle or left bundle branch block area, interest in AVNA has resurged.
   
   
3. A recent network meta-analysis found that a pace-and-ablate approach, compared with AF ablation or pharmacotherapy, had the lowest rates of rehospitalization, cardiovascular mortality, all-cause mortality, and stroke. AF ablation had the lowest rate of AF recurrence.
   
   
4. Pacing options with AVNA include RV pacing, biventricular pacing, His bundle pacing, and left bundle branch area pacing (LBBAP). 
   
   
5. Biventricular pacing eliminates the dyssynchrony induced by RV pacing, but creates dyssynchrony in patients with baseline narrow QRS. AVNA with biventricular pacing should principally be used in patients with HF and a wide baseline QRS interval >120 milliseconds.
   
   
6. His bundle pacing preserves ideal biventricular stimulation and narrow QRS, but is technically challenging due to the close proximity of the pacing electrode and ablation site. 
   
   
7. LBBAP is achieved by penetrating the interventricular septum to capture the left bundle, and maintains near-normal LV electrical activation. However, left bundle capture cannot always be obtained. 
   
   
8. If electrical synchronization is suboptimal with His bundle pacing or LBBAP, placement of a coronary sinus lead may be necessary to optimize cardiac resynchronization therapy. 
   
   
9. Conduction system pacing cannot currently be recommended as a first-line alternative for cardiac resynchronization for HF with reduced ejection fraction (HFrEF) with either sinus rhythm or AF, as there has been no randomized controlled trial demonstrating its superiority or noninferiority to biventricular pacing. 
   
   
10. LBBAP may carry the overall advantage over His bundle pacing:
    1. LBBAP has better implant success rates, improved pacing parameters, and fewer late lead-related complications.
    2. Advantages of His bundle pacing are a higher rate of conduction system capture and physiologic activation of the right and left ventricles in patients with narrow QRS.
       
       
11. AVNA with pacemaker implantation always results in pacemaker dependency. Other complications of the pace-and-ablate strategy can include pacing-induced cardiomyopathy, pneumothorax, infection, hematoma, perforation, lead dislodgement, tricuspid regurgitation, vascular access complications, required generator changes in a pacemaker-dependent patient, and sudden cardiac death. The overall complication rate has historically ranged from 0.8% to 1.8% and has likely decreased in the more than 20 years since these were reported.
    
    
12. Ongoing clinical trials include:
    1. PACE-FIB, which compares LBBAP plus AVNA versus pharmacological rate control in patients with permanent AF and HF with preserved or minimally reduced EF.
    2. ABACUS, which compares AVNA plus conduction system pacing versus pulmonary vein isolation (with additional lesions if needed) in patients with persistent AF and symptomatic HF who are >60 years of age

https://academic.oup.com/eurheartj/article/45/46/4887/7821007