PO-03-065 PULSED FIELD ABLATION IS MORE EFFECTIVE THAN RADIOFREQUENCY ABLATION FOR THE RETREATMENT OF CHRONIC ABLATION SUBSTRATE

There are known limitations of radiofrequency ablation (RFA) in extending and homogenizing prior ablation. The effect pulsed field (PFA) following RFA is not known. To evaluate the differential ability PFA versus to penetrate chronic lesions. A two step in-vivo study was designed simulate a retreatment scenario. Step I : Six Yorkshire swine underwent intentional ineffective using IntellaNav StablePoint catheter three sites: I.1) Right atrium: intercaval line with multiple gaps, I.2) Left right superior inferior common pulmonic veins I.3) ventricle: discrete II: Following survival period ≈5 weeks animals were remapped. Chronic identified via voltage mapping. Next, retreated as following: II.1) over focal (FARAPOINT), II.2) vein isolation single shot (FARAWAVE), II.3) randomized into arms, or RFA. In each arm, types sub-chronic lesions performed: on scar healthy myocardium. applied 4 applications 2.0kV. 30W, 60s local impedance drop >50Ω. After 2-5 day survival, atrial electrical block assessed electroanatomical All measured sub-gross for extent zones. left atria: Retreatment resulted complete (width: 16-28mm) all targeted veins, expanding disparate mean depth 4.8±1.4mm. When performed substrate, zone 7.6±1.3mm, compared 3.9±1.6mm when (p<0.01). contrast, substrate 7.0±1.6mm, similar (7.1±1.3mm; p=0.94) demonstrating that has scar. may be advantageous RFA, producing that, unlike retreatment, significantly impeded by presence from