title: Finite element analyses of uniform current density electrodes for radio-frequency cardiac ablation.
abstract: The high current density at the edge of a metal electrode causes hot spots, which can lead to charring or blood coagulation formation during radio-frequency (RF) cardiac ablation. We used finite element analysis to predict the current density distribution created by several electrode designs for RF ablation. The numerical results demonstrated that there were hot spots at the edge of the conventional tip electrode and the insulating catheter. By modifying the shape of the edge of the 5-mm tip electrode, we could significantly reduce the high current density at the electrode-insulator interface. We also studied the current density distribution produced by a cylindrically shaped electrode. We modified the shape of a cylindrical electrode by recessing the edge and filled in a coating material so that the overall structure was still cylindrical. We analyzed the effects of depth of recess and the electrical conductivity of the added material. The results show that more uniform current density can be accomplished by recessing the electrode, adding a curvature to the electrode, and by coating the electrode with a resistive material.
authors.affiliation: Department of Electrical and Computer Engineering, University of Wisconsin-Madison 53706, USA.
authors.forename: S
authors.initials: S
authors.lastname: Tungjitkusolmun
authors.forename: E J
authors.initials: EJ
authors.lastname: Woo
authors.forename: H
authors.initials: H
authors.lastname: Cao
authors.forename: J Z
authors.initials: JZ
authors.lastname: Tsai
authors.forename: V R
authors.initials: VR
authors.lastname: Vorperian
authors.forename: J G
authors.initials: JG
authors.lastname: Webster
mesh_terms: D017115:Catheter Ablation / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible; D004553:Electric Conductivity; D004566:Electrodes; D004867:Equipment Design; D006358:Hot Temperature; D008422:Materials Testing; D008962:Models, Theoretical; D011846:Radio Waves; D013499:Surface Properties
chemical_list: D020099:Coated Materials, Biocompatible