Background: Ventricular rate control is essential in the management of atrial fibrillation. Atrioventricular node ablation (AVNA) and ventricular pacing can be an effective option when pharmacological rate control is insufficient. However, right ventricular pacing induces ventricular desynchronization in patients with normal QRS and increases the risk of heart failure on long term. His bundle pacing (HBP) is a physiological alternative to RVP. Observational studies have demonstrated its feasibility but there is still very limited data about the feasibility of AVNA after HBP.
Objective: To evaluate feasibility and safety of HBP followed by AVNA in patients with non-controlled atrial arrhythmia.
Methods: We included all patients who underwent AVNA for non-controlled atrial arrhythmia after HBP implantation in three hospitals. No back-up right ventricular lead was implanted. AVNA procedures were performed with 8 mm-tip ablation catheter. Acute HBP threshold increase during AVNA was defined as a threshold elevation > 1V.
Results: AVNA after HBP lead implantation was performed in 38 patients. HBP and AVNA were performed simultaneously during the same procedure in 10. AVNA was successful in 29 of 38 patients (76%). Modulation of the AV node conduction was obtained in 5 patients (13%). The mean procedure duration was 50±11min, and mean fluoroscopy duration was 8±3min. A mean number of 7.8±3.2 RF applications (430±185 sec) were delivered to obtain complete / incomplete AV block. Acute HBP threshold increase occurred in 7 patients (18.4%) with return to baseline value at day 1 in the majority of them (5). There was no lead dislodgment. Mean HBP threshold at implant was 1.39±0.25V@0.5ms and did not increase at 3 months follow-up (1.29±0.25V@0.5ms). AV node re-conduction was observed in 5 patients (17.2%). No ventricular lead revision was required during the follow-up period. The baseline native QRS duration was 105±8ms and the paced QRS duration was 109±6ms.
Conclusion: AVNA combined with HBP for non-controlled atrial arrhythmia is feasible and does not compromise HBP but seems technically difficult with significant AV nodal re-conduction rate. The presence of a back-up ventricular lead could have changed our results and therefore would require further evaluation.