B-PO03-133 BIPOLAR RADIOFREQUENCY ABLATION USING ANGIOPLASTY GUIDEWIRES

Abstract

Intramural ventricular arrhythmias represent a challenge for catheter ablation. Angioplasty guidewires can be used to map septal coronary veins that are inaccessible to standard ablation catheters and eventually could have a role in the ablation of septal arrhythmogenic substrate. To evaluate the feasibility of bipolar radiofrequency (RF) ablation using an angioplasty guidewire as the return electrode. An ex-vivo model consisting of a piece of porcine myocardium submersed in a normal saline bath was used. RF energy was applied between an irrigated ablation catheter (Tacticath, Abbott) positioned on the endocardial surface and a partially coated angioplasty guidewire (Luge, Boston Scientific) placed on the adjacent epicardial surface, connected to the indifferent port of the RF generator. RF applications using powers between 20-50W resulted in effective lesion formation on both sides of the ventricular myocardium, but powers ≥30W were associated with a higher incidence of steam pops. When a power of 20W was applied (25 lesions) the baseline impedance was 180±22 Ω, with impedance drop of 44±17 Ω and no steam pops. The lesion volume was 237±182 mm3 and transmural lesions were observed in tissues measuring 10-15 mm thickness (Figure: In the left panel the orientation of the electrodes is oblique, resulting in 2 separate lesions; in the right panel both electrodes are directly opposed, resulting in a transmural lesion core). Bipolar RF ablation between an ablation catheter and an angioplasty guidewire is feasible and may result in transmural lesions. Further studies are required to confirm the efficacy and safety of this ablation approach.