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PO-710-06 ASSESSMENT OF LESION DURABILITY PRODUCED BY PULSED ELECTRIC FIELD ABLATION: EVALUATION IN A SWINE ATRIAL LINEAR LESION MODEL

      Background

      Pulsed electric field (PEF) ablation may cause durable or transient injury to cardiac myocytes.

      Objective

      To examine acute and chronic integrity of the line of conduction block produced by PEF ablation in a swine heart model.

      Methods

      A 7F catheter with a 3.5 mm ablation electrode (TactiCath, Abbott) was connected to a PEF generator (CENTAURI, Galaxy Medical) and positioned in RA and LA under EnSite guidance in 4 closed chest pigs. Using the lowest energy output settings of the PEF system (19 A, 1.4 ms), biphasic PEF current was delivered between the ablation electrode and a skin patch. A total of 10 linear ablations were performed in the SVC (n=3), inter-caval region (n=4) and right superior pulmonary vein (n=3) using point-by-point ablation (average CF: 15 g) with different inter-lesion distances (ILD): 12-15 mm (n=1), 6-8 mm (n=5) and 4 mm (n=4). Conduction block/isolation was assessed acutely (4 pigs) and 14 days (3 pigs) after index procedures.

      Results

      Complete elimination of electrograms on the ablation catheter was typically observed after the first PEF application. Complete line of block/isolation was obtained acutely in all 10 lines, confirmed by EnSite activation and voltage maps. At 14 days, recovery of conduction was observed in 4/5 (80%) lines with 6-8 mm ILD and 0/4 lines with 4 mm ILD (p<0.05). Gaps in linear lesions were confirmed by gross pathology in 4 lines with reconnection using TTC staining.

      Conclusion

      At the lowest PEF dose, acute conduction block can be consistently achieved with large ILD. While all 4 mm ILD lesions remained durable, recovery of conduction at 14 days was often observed for ILD≥ 6 mm, suggesting durable lesion sizes between 4-5 mm surrounded by transiently stunned myocardium.
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