Abstract 17825: Pulmonary Vein Isolation With a Single Encircling Lesion in Less Than 15 seconds: a New Catheter-Based Intra-Pericardial Ablation System
Introduction: We are developing a catheter-based intra-pericardial single-shot pulmonary vein isolation (PVI) procedure. However, left atrial (LA) ablation from within the pericardial space introduces a number of technical challenges leading us to evaluate a kilovolt-range microsecond direct current ablation technique.
Hypothesis: Our novel DC ablation system can safely produce a transmural contiguous ablation lesion in a chronic animal model.
Methods: In 5 anesthetized pigs an over-the-wire 30-electrode catheter ablation system was positioned around the posterior LA encircling all pulmonary veins from within the pericardial space. Kilovolt-range (500 V n=1 & 1000 V n=4), bipolar, 100 us, DC impulses were delivered in a synchrony with cardiac pacing (120 pps). At 8 days the terminal procedure was performed. Triphenyltetrazolium solution was given prior to postmortem and histologic evaluation of the treatment zone and nearby structures.
Results: All 5 animals tolerated the procedure and survived without serious complications (survival of 177.80 ± 11.6 hours). Over-the-wire ablation catheter positioning required 4.4 ± 2.94 minutes. Average ablation time was 11.7 ± 1.2 seconds resulting in a dramatic attenuation in the local epicardial electrograms amplitude [mean amplitude 64% reduction (range 21%-88%) pre 2.13 ± 1.11 mV post 0.75 ± 0.45 mV, p<0.05]. No arrhythmias or significant hemodynamic change occurred. Necropsy revealed transmural (n=4/4), contiguous (n=4/4), linear encircling lesion encompassing the PVs and LA (1000 V impulse group). A transmural but non-contiguous lesson occurred in the animal receiving 500 V impulses. There was no gross evidence of focal injury to the adjacent structures, lungs, esophagus, and phrenic nerve. Tissues histology along the treatment zone confirmed well demarcated and consistently transmural lesions (range 1-8 mm depth).
Conclusions: The DC ablation technique is effective and remarkably fast with total ablation time taking less than 12 seconds. The technique appears well tolerated with no substantial evidence of significant collateral damage to bystander anatomy. Further study is needed to understand optimal dosing and safety prior to human studies.
Author Disclosures: S.R. Mickelsen: Ownership Interest; Significant; Iowa Approach Inc.. G. Long: None. W. Lumpp: None. E. Sauter: None. O. Mesubi: None. J. Martins: None.
- © 2014 by American Heart Association, Inc.