title: Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: computer modelling comparing bipolar and unipolar modes.
abstract: OBJECTIVE
  The aim of this study was to compare the efficacy of bipolar (BM) vs. unipolar (UM) mode of radiofrequency ablation (RFA) in terms of creating transmural lesions across the interventricular septum (IVS) and ventricular free wall (VFW).
  
  
  METHODS
  We built computational models to study the temperature distributions and lesion dimensions created by BM and UM on IVS and VFW during RFA. Two different UM types were considered: sequential (SeUM) and simultaneous (SiUM). The effect of ventricular wall thickness, catheter misalignment, epicardial fat, and presence of air in the epicardial space were also studied.
  
  
  RESULTS
  Regarding IVS ablation, BM created transmural and symmetrical lesions for wall thicknesses up to 15 mm. SeUM and SiUM were not able to create transmural lesions with IVS thicknesses ≥12.5 and 15 mm, respectively. Lesions were asymmetrical only with SeUM. For VFW ablation, BM also created transmural lesions for wall thicknesses up to 15 mm. However, with SeUM and SiUM transmurality was obtained for VFW thicknesses ≤7.5 and 12.5 mm, respectively. With the three modes, VFW lesions were always asymmetrical. In the scenario with air or a fat tissue layer on the epicardial side, only SiUM was capable of creating transmural lesions. Overall, BM was superior to UM in IVS and VFW ablation when the catheters were not aligned.
  
  
  CONCLUSIONS
  Our findings suggest that BM is more effective than UM in achieving transmurality across both ventricular sites, except in the situation of the epicardial catheter tip surrounded by air or placed over a fat tissue layer.
authors.affiliation: Biomedical Synergy, Electronic Engineering Department, Universitat Politècnica de València , Spain .
authors.forename: Ana
authors.initials: A
authors.lastname: González-Suárez
authors.forename: Macarena
authors.initials: M
authors.lastname: Trujillo
authors.forename: Jacob
authors.initials: J
authors.lastname: Koruth
authors.forename: Andre
authors.initials: A
authors.lastname: d'Avila
authors.forename: Enrique
authors.initials: E
authors.lastname: Berjano
mesh_terms: D062906:Cardiac Catheters; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D006352:Heart Ventricles / Q000601:surgery*; D008962:Models, Theoretical
keywords: Bipolar ablation; interventricular septum; radiofrequency ablation; unipolar ablation; ventricular ablation; ventricular free wall