Comparison of characteristics and acute ablation outcome of atrial fibrillation drivers detected using octaray vs. pentaray catheter
Authors: Tomura N , Senoo K , Makino M , Munakata J , Shimoo S , Iwakoshi H , Nishimura T , Miki T , Kato Y , Kitajima H , Nishiuchi S , Kakita K , Sato D , Shiraishi H , Matoba S 
Published: October 2024

Abstract

Background
Atrial fibrillation (AF) driver ablation is proposed as treatment strategy beyond pulmonary vein (PV) isolation in persistent AF patients. The CARTOFINDER mapping system (Biosense Webster Inc.) can depict two types of activation patterns, focal and rotational activation, using unipolar potentials during AF. Recently, an 8-spline 48-electrodes mapping catheter (OctaRay) was developed.

Purpose
To evaluate the characteristics of AF drivers detected by CARTOFINDER using the OctaRay catheter and the acute termination compared to previous mapping catheter (PentaRay).

Methods
This is a multicenter prospective observational study from 6 hospitals where 47 persistent AF patients underwent initial catheter ablation from April to December 2023. We assessed the frequency and distribution of AF drivers in both atrium identified by CARTOFINDER using the OctaRay catheter before procedure. After PV isolation, additional ablation was performed on high-repetitive activations (focal activation&gt;22 repetitions, rotational activation&gt;17 repetitions) and the rate of acute AF termination was evaluated. Acute AF termination was defined as transition to sinus rhythm or atrial tachycardia (AT). The results were compared to 29 patients in whom the PentaRay catheter was used from September 2022 to March 2023.

Results
The mean age of OctaRay group was 72.0±8.6 years. The median AF duration was 0.7 years, and the prevalence of long-standing AF was 26%. All clinical characteristics was not significantly different between OctaRay and PentaRay group. Focal activation was more frequently identified in OctaRay group than in PentaRay group (94.1points/patient vs. 36.3points/patient, P&lt;0.01), especially in anterior (P&lt;0.01) and posterior (P&lt;0.01) of right atrium (RA), posterior (P&lt;0.01), roof (P&lt;0.01) and lateral (P&lt;0.01) of left atrium (LA), and PV antrum (P&lt;0.01), respectively. Rotational activation was also more frequently identified in OctaRay group (54.7points/patient vs. 2.6points/patient, P&lt;0.01), especially in anterior (P=0.02) and posterior (P=0.03) of RA, and anterior of LA (P=0.02), respectively. Furthermore, high-repetitive focal activation was more frequently identified in OctaRay group than in PentaRay group (P&lt;0.01). On the other hand, the frequency of high-repetitive rotational activation was not significantly different between the two groups (P=0.63) (Figure A). In OctaRay group, high-repetitive focal activation was frequent in anterior of RA (72.3%) and LA appendage (48.9%) (Figure B), and had significantly shorter AF cycle length compared to the entire atrium (156ms vs. 162ms, P&lt;0.01). Ablation for high-repetitive activations after PV isolation resulted in 12.8% acute AF termination in OctaRay group, significantly higher than in PentaRay group (vs. 0%, P=0.04).

Conclusion
The OctaRay catheter have the potential to detect more frequent and accurate AF drivers than the PentaRay catheter, leading to the improvement of acute AF termination.