RESUMO
BACKGROUND: Currently, 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 deeper than currently available 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 a FEF catheter with a truncated dome-shaped tip, creating a toroidal ablating surface. 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 ± 1.0 mm wide by 6.1 ± 1.1 mm deep with ablation using a conventional irrigated tip catheter (Thermocool SF). In contrast, lesions created using FEF ablation were 12.8 ± 1.6 mm wide and 14.0 ± 1.6 mm deep. Steam pops were less frequent in the FEF group. 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 15 mm. CONCLUSION: This study is the first proof of concept of FEF technology. Using a novel toroidal 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 inherent to current RF catheter designs. FEF ablation may allow delivery of deeper ablations lesions with potentially lower risk of tissue hyperthermia than conventional catheters. Future studies are needed.
