Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Ablation Techniques D-AB24 - Efficacy, Safety, and Potential Advantages of a New Energy Source for Catheter Ablation of Myocardial Tissue (ID 21) Abstract

D-AB24-02 - Acute Pulmonary Vein Ablation Using Nanosecond Pulsed Electric Fields (ID 799)


Background: Pulmonary veins (PV) play a critical role in atrial fibrillation (AF). Isolating or ablating this arrhythmic focus is a pillar of AF treatment. We have previously demonstrated PV ablation without resultant PV stenosis using microsecond pulsed electric fields (PEF). Nanosecond PEF (nsPEF) offers the potential advantage of less muscle stimulation.
Objective: We explored whether acute PV ablation can be accomplished with nsPEF.
Methods: In two canine models, general anesthesia was administered along with paralytics prior to monopolar nsPEF. Ablation catheters were placed in the left pulmonary veins via transeptal access (Figure 1A). Baseline electrograms and thresholds were recorded before and after PEF sequences from stationary catheters. Energy was delivered using a CellFX™ generator (Pulse Biosciences, Hayward, CA) in monopolar and bipolar configurations.
Results: In both animals, baseline pulmonary vein capture thresholds were 0.6-3.2 mA @ 0.5 ms. Post nsPEF delivery (3.0 to 33.4 Joules), amplitudes of pulmonary vein electrograms were significantly decreased while tissue capture was absent (Figure 1A and 1B). nsPEF sequences used to complete PV ablation took <1 minute. Muscle contractions were observed with energy delivered via monopolar but not bipolar nsPEF sequences. No ventricular arrhythmia was noted. When more than 1 nsPEF sequence was used, there was incremental increase in capture thresholds and decrease in EGM amplitude. All effects persisted beyond 30 minutes of energy delivery after which the animal was euthanized.
Conclusion: In acute canine experiments, nsPEF delivered using a stationary ablation catheter was able to acutely ablate pulmonary veins.