Long-term results of cardioneuroablation evaluated by implantable loop recorder
Authors: Quintal J , Parreira L , Mesquita D V , Marinheiro R , Chambel D , Encarnacao C , Lopes C , Goncalves A , Ferreira D , Lopes M J , Ferreira J S , Coelho R A , Pohle C L , Bernardes P , Seixo F 
Published: May 2024

Abstract

Background
Cardioneuroablation (CNA) is a catheter ablation technique based on radiofrequency application in the atrial endocardium to decrease vagal response. Since the first series publication, its use has greatly increased, with CNA being now used in vasovagal syncope (VVS), functional atrioventricular block (AVB), symptomatic sinus bradycardia (SB) and Atrial Fibrillation (AFib). There is still limited data regarding long-term follow-up (FUP) of patients who have undergone this procedure.

Purpose
The aim of this study was to evaluate long-term results of CNA in a single center with the use of an implantable loop recorder (ILR).

Methods
We performed a prospective single-center cohort study. Patients with significant documented functional bradyarrhythmias between September 2019 and October 2023 were enrolled. All patients underwent ILR implantation before ablation. CNA was performed using catheter ablation aiming at right epicardial GPs with 3-dimensional electroanatomical mapping support. A 2 mg atropine test (bolus) was carried out before and after CNA and the subsequent heart rate (HR) increase registered. Successful CNA was defined as absence of HR increase with atropine after the ablation.
HR pre and post ablation was compared. Immediate and late procedure complications were assessed. Recurrence of symptoms, the presence significant vagal-induced bradyarrhythmias on ILR and the need for pacemaker (PM) implantation were also assed.

Results
Fifteen patients (pts) were included, with a mean age of 64 (± 12 years) and a 53.3% male prevalence. None of the pts had structural heart disease. The main indication for CNA was AFib with brady-tachy syndrome (8 pts, 53.3%), followed by VVS (4 pts, 26.7%), SB (2 pts, 13.3%) and AVB (2:1 AVB; 1 pt). The most common symptom was syncope (46.7%), followed by pre-syncope (40%) and fatigue (20%).
There was a significant improvement in HR after CNA (55 ± 13 vs. 67 ± 14 bpm pos-CNA, p=0.002). The achievement of success was verified in all patients (mean HR variation with atropine before CNA 35 ± 10% vs. 2 ± 2% after CNA; p=0.001). Procedure mean time was 28 ± 12 min.
During a maximum FUP of 48 months (minimum 1 month, median 5), 1 patient had recurrence of VVS with a 10s pause documentation on ILR requiring PM implantation and 1 patient had a 4s pause without translation into symptoms and a duration decreasing tendency during FUP. Freedom from recurrence of symptoms was 93.3%, freedom from pacemaker implantation was 93.3% and freedom from significant bradyarrhythmias was 86.7% – Figure 1. No immediate or long-term complications were seen.

Conclusions
CNA aiming at the right GPs is a safe and quick procedure for patients with functional bradyarrhythmias. This ablation technique in most patients not only reduces symptoms, but also avoids early PM implantation, therefore improving quality of life. Further randomized clinical trials are needed to support these data and refine patient selection criteria.