Focused Electric Field Ablation: A Novel Technology to Increase Ablation Lesion Depth With Improved Safety

Background: RF ablation is limited in its ability to deliver deep lesions, as most of the energy delivered to the tissue is dissipated in the first few millimeters from the catheter tip. Focused Electric Field (FEF) is a novel technology with the potential to ablate much deeper than current RF catheters. This work is the first proof of concept of FEF technology. Objective: To introduce FEF technology and demonstrate its feasibility as an ablation tool. Methods: We constructed an FEF catheter with a hemispherical concave tip. We performed ablation ex vivo in porcine hearts and examined ablation characteristics using both tissue sectioning and real-time thermal imaging. Results: RF lesions were 9.1{plus minus}1.0mm wide by 6.1{plus minus}1.1mm deep with ablation using an irrigated tip catheter (Thermocool SF). In contrast, lesions created using FEF ablation were 16.1{plus minus}2mm wide and 15.2{plus minus}1.1mm deep. Steam pops were much less frequent with FEF technology (6.7% incidence for FEF vs. 38% with Thermocool). Thermal imaging demonstrated that in contrast to an irrigated tip RF catheter, the FEF catheter generated a uniform temperature profile down to a maximum depth exceeding 15mm. Conclusion: This study is the first proof of concept of FEF technology. Using a novel concave catheter tip design the electric field remains confined to a narrow tissue region thus avoiding the rapid fall off in energy delivery from the tissue surface that is inherent to current RF technology. FEF ablation has the potential to allow significantly deeper ablation than current RF catheter technologies with an improved safety margin.