421 CARDIO-NEURO ABLATION WORKFLOW OPTIMIZATION USING THE CARTO 3 SYSTEM CFAE MODULE
Authors: Valli Federica , Saviano Massimo , Toriello Filippo , Pollina Alberto , Carugo Stefano 
Published: December 2022

Abstract

Introduction
Ganglionated Plexi (GP) ablation has been revived by the recent interest in cardioneuroablation (CNA) in the field of vasovagal syncope (VVS). Many small observational studies and a multicenter registry showed a valuable effect of GP ablation on vagal hyperactivity modulation, eliminating the need for a permanent pacing device implantation in both functional atrioventricular block (AVB) and sinus node block (SNB). We suggest a standardized approach to fragmented activity signal analysis and automated workflow using CARTO3 mapping system (Johnson & Johnson Biosense Webster Inc., CA, USA) built-in CFAE software to pursue vagal denervation in different clinical settings.

Methods
The first patient enrolled was a 28-year-old lady admitted to the emergency department of IRCCS Cà Granda Hospital, in Milan, for yet another episode of syncope of undetermined origin complicated by facial trauma. Since the rest electrocardiogram (ECG) was completely normal and family screening was negative for sudden cardiac death (SCD), we decided for long term ECG monitoring with an implantable loop recorder (ILR). During follow-up, another traumatic syncope occurred and a 26 sec sinus arrest interrupted by a single escape beat was recorded. We advised a pacemaker implant proposing the CNA as a therapeutic alternative.
Technique: We used CARTO3 mapping system and the ablation and mapping catheter for electroanatomical model creation of both atria. Left atrial access was granted via transeptal puncture using a Brockenbrough Needle (BRK1, Abbott) and a Preface 8.5 f transeptal sheath. We used the complex atrial fractionated electrograms (CFAE) software to localize the GP. The target signal was characterised by more than 3 deflections, named confidence interval levels (ICL) on the system, lasting at least 2 msec each and an amplitude above 0.06 millivolts. Since the system acquires points analyzing 2.5 sec (2 sec before and 0.5 sec after the reference), in this time the total number of ICL is strongly dependent on the heart rate (HR). The settings for the color bar confidence level extremities should be established considering the number of beats every 2.5 sec and the desired minimum number of ICL plus the ventricular deflection in the areas surrounding the mitral and tricuspid valves. It must be considered that this feature, whose intention was to map AF, interferes with the accuracy of the window of interest including the ventricular far fields in the counts. We choose duration value intervals ranging from 2 msec, to include rapid deflections of the fragmented activity, to 140 msec to be as inclusive as possible. The selected threshold values ranged from 0.06 millivolts, in order to exclude noise and necrotic areas, to 1.5 millivolts, trying to avoid ventricular far field signals. We set the color bar limits from 15 to 20, eliminating the less fragmented signals as we decided to target areas with more than 7 deflections (Figure 1).
The maps we obtained showed fragmented activity in the areas corresponding to the right superior GP in the superior vena cava, the right inferior GP close to the fossa ovalis, the left superior GP on the anterior aspect of the left superior pulmonary vein antrum and the left posteromedial GP in the posteromedial region, behind the aortic non coronary cusp. We started the CNA in the right atrium and then in the left atrium and we observed progressive increase of HR. ILR monitoring after ablation highlighted a reduction of daily heart rate variability and an increase of average heart rate especially at rest, confirming the effectiveness of CNA.

Conclusions
We find that CARTO3 mapping system may be used for GP detection and ablation as effectively as other mapping systems in a “non-visual” approach. Automatization and optimization of the workflow requires further improvements in the CFAE module. The opportunity to avoid device implantation in younger with functional syncope is, in our humble opinion, a milestone in the history of electrophysiology. In our ongoing center experience, the GP ablation is proving to be a promising option also for quality of life improvements in brady-tachy patients.