title: Lesion formation by ventricular septal ablation with irrigated electrodes: comparison of bipolar and sequential unipolar ablation.
abstract: BACKGROUND
  Ablation of ventricular tachycardia originating from the interventricular septum (IVS) is often limited by the presence of re-entrant pathways deep in the IVS. We compared the efficacy of bipolar ablation vs. sequential unipolar ablation in creating a transmural lesion across the porcine IVS.
  
  
  RESULTS
  Seventeen excised swine hearts were superfused by pulsatile saline flow. Bipolar ablation (at 30 W, 50 W or 70 W for 120 s) was performed between 2 saline-irrigated (20 ml/min) 4-mm tip electrodes, 1 on the left and 1 on the right side of the IVS. Sequential unipolar ablation (at 30 W, 50 W or 70 W for 120 s) was performed on the left and right sides of the IVS with an irrigated-tip catheter. Bipolar ablation produced a narrower, deeper lesion than did unipolar ablation. A transmural lesion was created by sequential unipolar ablation in 7.7%, 8.3% and 0% of tissue preparations and by bipolar ablation in 50.0%, 46.7% and 71.4% of tissue preparations at 30 W, 50 W and 70 W.
  
  
  CONCLUSIONS
  Bipolar ablation of the IVS was highly effective for creating a transmural IVS lesion.
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nagashima
authors.forename: Ichiro
authors.initials: I
authors.lastname: Watanabe
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Okumura
authors.forename: Kimie
authors.initials: K
authors.lastname: Ohkubo
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kofune
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ohya
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kasamaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirayama
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D023421:Models, Animal; D013552:Swine; D017180:Tachycardia, Ventricular / Q000601:surgery; D054088:Ventricular Septum / Q000473:pathology* / Q000601:surgery*