PO-02-245 THE IMPACT OF PULSED FIELD ABLATION ON CONDUCTION VELOCITY OVER TIME

Abstract

Pulsed field ablation (PFA) is an emerging technology that has both reversible and irreversible effects. However, the time course of reversibility of atrial conduction velocity after PFA has not been well characterized. To determine changes in conduction velocity over time after PFA Nine pigs were studied. The Medtronic PVAC GOLD catheter was placed in the superior vena cava (SVC), right atrium (RA), left atrial appendage (LAA) and left pulmonary vein (LPV). One and four trains at 1000 V and 1500V were delivered at these four sites in a random fashion. Activation mapping was done at baseline and 10-20 minute intervals post ablation using ESI mapping system. Conduction velocity was obtained between a site of entry and exit identified by wavefront propagation in the scar at the 5-minute time point post ablation. Regional conduction slowing was defined as <31 cm/s and recovery was studied at 120 minutes time point. Recovery was defined as 50% recovery of baseline conduction velocity compared to the 5 minutes time point. The baseline conduction velocity was >100 cm/s across all experimental conditions. At 1000V x 1 and 1000V x 4 application, the average velocity was 21[HDM1] ±9 cm/s and 44 ±30 cm/s respectively. At 1500V x 1 and 1500V x 4 application, the average velocity was 27 ±16 cm/s and 33 ±15 cm/s respectively. The lowest conduction velocity occurred at the 5-minute time point (31 cm/s (5-100 cm/s). At 1000V x 1 and 1000V x 4 application, 2/8 and 2/8 animals recovered conduction at 120 min respectively. At 1500V x 1 and 1500V x 4, 1/8 animals and 0/8 animals recovered conduction at 120 min respectively. Median time to conduction recovery was 72 min (25-160 min). (Figure 1) Recovery of conduction is observed post PFA, more often with lower voltage ablations in this porcine model. The time course of conduction velocity recovery exceeds the standard clinical post ablation wait time suggesting that retesting for conduction block 20 min post ablation may be of limited value.