PO-02-003 IDENTIFICATION OF AREAS OF ANISOTROPIC CONDUCTION USING OMNIPOLAR TECHNOLOGY TO PREDICT FIRST-PASS ISOLATION AND RECONNECTION OF THE POSTERIOR WALL

Abstract

Posterior wall isolation (PWI) can be a useful adjunct to pulmonary vein isolation (PVI) for the management of persistent atrial fibrillation (AF). Successful isolation of the posterior wall is challenging, with first-pass isolation rates under 40%. Difficulties in achieving block may be due to inability to create transmural lesions due to complex posterior wall architecture from septopulmonary (SPB) and septoatrial (SAB) bundle insertion. Activation mapping using omnipolar technology (OT) may allow identification of areas of anisotropic conduction that represent atrial fiber and bundle insertion points to target for additional ablation. Correlate areas of anisotropy to first-pass isolation of the posterior wall and determine whether anisotropy can predict sites requiring additional ablation to achieve bidirectional block We retrospectively analyzed patients with persistent AF who underwent first-time PVI with PWI from November 2020 to December 2022 at a single tertiary referral center with using the EnSite X mapping system with OT (Abbott, IL). Demographic and procedural information was collected. The posterior wall was divided into 6 regions and areas of anisotropy, defined as an abrupt pivot or collision in OT vectors, along with mean and maximum bipolar voltage were recorded. Areas requiring additional ablation to achieve bidirectional block were recorded. 17 patients were included in our cohort, of which 5 had first-pass isolation (29%). Final isolation of the posterior wall was achieved in all cases. There were no significant differences in patient demographics. Total ablation times were significantly less in the first-pass group (2174 versus 1721 seconds, p = 0.035). Anisotropic areas were present in 80% of first-pass cases versus 75% of cases without first-pass. While overall PW voltage was similar in both groups, voltage at sites of anisotropy was significantly higher in patients without first-pass (6.8 vs 2.6, p = 0.024). In patients without first-pass, reconnection was at site of anisotropy in 50% of cases with mean bipolar voltage 7.4mV. Activation mapping using OT may help identify areas of anisotropic conduction that are common sites of epicardial connections. Targeting these areas with additional ablation may improve rates of first-pass isolation and reduce rates of chronic reconnection. Further investigation and a larger cohort is needed to validate the predictive utility of OT.