title: Off-pump epicardial atrial fibrillation surgery utilizing a novel bipolar radiofrequency system.
abstract: BACKGROUND
  Over the past several years, pulmonary vein isolation for the treatment of atrial fibrillation has gained significant popularity. This study was undertaken to evaluate a novel radiofrequency (RF)-enabled clamp system designed to create transmural lesions epicardially on the beating heart using bipolar RF.
  
  
  METHODS
  A set of differently shaped clamps modified to deliver bipolar RF energy were used to create a series of lesions in a beating heart canine model. The pulmonary veins and atrial appendages of 6 dogs were electrically isolated using bipolar RF energy. The right and left atrial appendages served as controls for the right and left pulmonary veins, respectively. Temperature-controlled RF energy was delivered to maintain a tissue temperature of 80 degrees C for 15 seconds. Electrical isolation was assessed acutely and after 4 weeks by a bipolar pacing protocol.
  
  
  RESULTS
  A total of 24 circumferential lesions were created. By pacing analysis, 100% (24/24) of these lesions were electrically isolated acutely and 95% (19/20) were still isolated 4 weeks later. At 4 weeks, 92% (22/24) of lesions were transmural by histologic analysis, and 96% (23/24) demonstrated endocardial continuity. One animal experienced a fatal cardiac arrhythmia during initiation of the post-survival procedure, prior to electrophysiologic evaluation, accounting for the reduced number of potential electrically isolated lesions.
  
  
  CONCLUSIONS
  Bipolar RF ablation utilizing a novel bipolar RF clamp device results in electrical isolation and histologic transmurality in an off-pump epicardial model.
authors.affiliation: Division of Cardiothoracic Surgery, Columbia-Presbyterian Medical Center, New York, New York, USA. dvigilance@gmail.com
authors.forename: Deon W
authors.initials: DW
authors.lastname: Vigilance
authors.forename: Mauricio
authors.initials: M
authors.lastname: Garrido
authors.forename: Mathew
authors.initials: M
authors.lastname: Williams
authors.forename: Elaine
authors.initials: E
authors.lastname: Wan
authors.forename: Ann
authors.initials: A
authors.lastname: Zeidner
authors.forename: Jennifer
authors.initials: J
authors.lastname: Casher
authors.forename: Aftab
authors.initials: A
authors.lastname: Kherani
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Morgan
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Naka
authors.forename: Craig
authors.initials: C
authors.lastname: Smith
authors.forename: Mehmet C
authors.initials: MC
authors.lastname: Oz
authors.forename: Michael
authors.initials: M
authors.lastname: Argenziano
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000601:surgery*; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D017115:Catheter Ablation / Q000295:instrumentation*; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D008297:Male