title: Comparison of high power, medium power, and irrigated-tip ablation strategies for pulmonary vein isolation in a canine model.
abstract: BACKGROUND
  We sought to compare the efficacy and collateral damage during pulmonary vein (PV) isolation in a canine model using three different ablation strategies.
  
  
  METHODS
  Normal dogs (three each) were randomized to high power (70 W, 20 seconds, 60 degrees C, Hi), medium power (50 W, 60 seconds, 50 degrees C; Med), or irrigated-tip (35 W, 60 seconds, 45 degrees C; Cool) ablation. Two transseptal punctures were performed and right and left superior PV electrical isolation was performed using the assigned ablation strategy. Animals survived for 30 days.
  
  
  RESULTS
  There was no difference in the number of lesions required to achieve PV isolation (Hi vs Med vs Cool; 43 vs 38 vs 44 lesions; P = NS). At sacrifice, Hi and Med lesions showed gross evidence of endocardial cratering and eschar formation. Corresponding histopathology showed transmural atrial necrosis with granulation tissue and fibrosis. Cool lesions demonstrated superficial endocardial white patches. The corresponding histopathology was subendocardial fibrosis with full and partial thickness necrosis of the atrial wall. One Hi animal had a large thrombus adherent to the left atrial wall above the left superior PV. PV stenosis was noted in one of three Hi and one of three Med, and none of three Cool. There were visible burns to the lung overlying the left atrial wall in one of three Hi, one of three Med, and none of three Cool. The esophagus demonstrated no evidence of serosal injury.
  
  
  CONCLUSIONS
  The Hi and Med power 8-mm-tip ablation strategies for achieving PV isolation appear to result in excessive tissue destruction. Irrigated-tip lesions resulted in less endocardial eschar formation, PV stenosis, and damage to collateral structures.
authors.affiliation: Section of Cardiac Electrophysiology, Division of Cardiology, University of Pennsylvania Health System, Philadelphia, Pennsylvania 19104, USA. edward.gerstenfeld@uphs.upenn.edu
authors.forename: Edward P
authors.initials: EP
authors.lastname: Gerstenfeld
authors.forename: Jason
authors.initials: J
authors.lastname: Jacobson
authors.forename: Victor
authors.initials: V
authors.lastname: Bazan
authors.forename: Sorin
authors.initials: S
authors.lastname: Lazar
authors.forename: John E
authors.initials: JE
authors.lastname: Tomaszewski
authors.forename: Francis E
authors.initials: FE
authors.lastname: Marchlinski
authors.forename: John
authors.initials: J
authors.lastname: Michele
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D004285:Dogs; D004735:Energy Transfer; D006329:Heart Conduction System / Q000473:pathology* / Q000601:surgery*; D011667:Pulmonary Veins / Q000473:pathology* / Q000601:surgery*; D007507:Therapeutic Irrigation / Q000379:methods*