title: Ablation of atrial fibrillation and esophageal injury: effects of energy source and ablation technique.
abstract: OBJECTIVE
  The aim of this study was the evaluation of histologic changes induced on the esophagus by surgical ablation therapy for atrial fibrillation.
  
  
  METHODS
  Experiments were performed on 39 sheep. Circular lesions were created endocardially or epicardially in the left atrium and at the pulmonary veins by using different energy sources: cryoablation, microwave, laser, and unipolar or bipolar radiofrequency. Temperatures inside the esophagus were measured, and esophageal tissue was investigated macroscopically and histopathologically.
  
  
  RESULTS
  Esophageal damage was seen histologically in 24 of 39 cases. The epithelium was intact in all cases. Unipolar radiofrequency induced the most intensive esophageal lesions in 4 of 6 cases. The affected areas were small (1.56-3.01 mm) but reached deep into the tissue. Endocardial cryoablation resulted in wider lesions (2.01-8.54 mm), which were intensive in only 2 of 6 cases. Epicardial cryoablation and bipolar radiofrequency induced wide (1.11-6.8 mm) but mainly mild alterations. Endocardial and epicardial microwave energy affected the esophagus in single cases, and lesions were small (0.97-2.81 mm). Only in 1 case did laser energy induce a moderate alteration (5.30 mm) of the esophageal wall.
  
  
  CONCLUSIONS
  Esophageal alterations were found in numerous cases. However, marked lesions were especially induced by endocardial unipolar radiofrequency and cryoablation.
authors.affiliation: Institute of Veterinary Pathology, Heart Center, University of Leipzig, Leipzig, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Aupperle
authors.forename: Nicolas
authors.initials: N
authors.lastname: Doll
authors.forename: Thomas
authors.initials: T
authors.lastname: Walther
authors.forename: Patrick
authors.initials: P
authors.lastname: Kornherr
authors.forename: Cris
authors.initials: C
authors.lastname: Ullmann
authors.forename: Heinz-Adolf
authors.initials: HA
authors.lastname: Schoon
authors.forename: Friedrich Wilhelm
authors.initials: FW
authors.lastname: Mohr
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods*; D003452:Cryosurgery / Q000009:adverse effects; D004947:Esophagus / Q000293:injuries* / Q000473:pathology*; D005260:Female; D007834:Lasers / Q000009:adverse effects; D008872:Microwaves / Q000009:adverse effects; D012756:Sheep