Abstract 10756: Utility of Simultaneous Multipolar Contact Sensing for Creation of Curvilinear Continuous Lesions for Pulmonary Vein Isolation Using a Multielectrode, Irrigated Catheter in the In Vivo Canine Heart
Introduction: Multielectrode catheter use for PVI is promising, but the success depends on the ability to create contiguous, transmural lesions during RF delivery. In an in vivo canine model, we determined tissue effects of simultaneous unipolar and bipolar energy deliveries via a novel, irrigated, curvilinear multielectrode catheter and assessed the impact of an impedance based contact sensing algorithm at each electrode prior to RF delivery on ablation line continuity.
Methods: A curvilinear, 10 electrode (3 mm long, 4 mm spacing), irrigated (6ml/min/electrode) catheter was used to create atrial lesions in 6 mongrel dogs. Sixty sec, temperature controlled (45°C) RF energy was delivered simultaneously in either unipolar (up to 25 W) or bipolar mode (up to15 W)(between pairs of consecutive electrodes). In 2 dogs, RF was delivered after catheter contact was judged by ICE, fluoroscopy and EGMs (group I), while in 4 dogs, RF was only delivered when ≥ 4 consecutive electrodes had adequate contact as sensed by the internal impedance based algorithm (group II). Lesions were examined at necropsy and sections from ablation lines from both groups were histologically compared.
Results: A total of 32, non-overlapping, multielectrode ablations (14 unipolar and 18 bipolar) were analyzed. There was no char or thrombus present. The max width of ablation lines in unipolar and bipolar group was comparable (7.64 ±1.01 vs. 6.99 ± 1.51mm; p =0.161), while the max depth was significantly larger in the unipolar group (4.81 ± 1.39 vs. 3.63 ± 1.44mm; p= 0.018). Histologically, 23/23 sections (100 %) from group II (10 unipolar and 13 bipolar) revealed transmural thermal injury and continuity compared to 23/25 sections (92%) from group I (4 unipolar and 5 bipolar)
Conclusions: Ablation guided by impedance based contact sensing at each electrode is a reliable means to produce contiguous and transmural linear lesions.Contact sensing facilitates both simultaneous unipolar and bipolar energy deliveries. In addition, simultaneous unipolar deliveries create deeper lesions than bipolar ones.
- © 2013 by American Heart Association, Inc.