title: Electrical isolation of the posterior left atrial wall and pulmonary veins for atrial fibrillation: feasibility of and rationale for a single-ring approach.
abstract: BACKGROUND
  Wide electrical pulmonary vein isolation (PVI) with two separate rings of ablation requires extensive ablation on the posterior left atrial wall close to the esophagus.
  
  
  OBJECTIVE
  The purpose of this study was to determine the feasibility of PVI using a single ring of radiofrequency ablation lesions.
  
  
  METHODS
  Irrigated-tip ablation catheters, deflectable sheaths, and computerized tomographic image integration were used to isolate the pulmonary veins and posterior wall of the left atrium in 41 patients with a single ring of radiofrequency ablation lesions. The procedural details were compared with a consecutive series of 41 historical controls who underwent PVI with two separate rings around the ipsilateral vein pairs.
  
  
  RESULTS
  Isolation with a single ring was possible in 39 of 41 cases. Ablation was required within the ring at the venous side of the ridge separating the left atrial appendage and left pulmonary veins (n = 17, 43%) or within the roofline (n = 16, 40%). The length of linear lesions adjacent to the esophagus was shorter in the single-ring group (19 +/- 10 mm vs. 31 +/- 14 mm; P = .01). The procedural times, number of ablation sites, duration of ablation required to achieve PVI, and rhythm outcomes at 6 months were similar in the two groups.
  
  
  CONCLUSIONS
  Radiofrequency ablation using an open irrigated-tip ablation catheter can be used to reliably electrically isolate the pulmonary veins with a single large circular lesion. PVI can be achieved with a similar procedural and ablation time. The major problem areas were identified as the roof of the left atrium and the ridge separating the left-sided veins from the left atrial appendage.
authors.affiliation: Department of Cardiology, Westmead and Westmead Private Hospitals, Westmead, Australia. stuartpt@yahoo.com
authors.forename: Stuart P
authors.initials: SP
authors.lastname: Thomas
authors.forename: Toon Wei
authors.initials: TW
authors.lastname: Lim
authors.forename: Rebecca
authors.initials: R
authors.lastname: McCall
authors.forename: Swee-Chong
authors.initials: SC
authors.lastname: Seow
authors.forename: David L
authors.initials: DL
authors.lastname: Ross
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy*; D016022:Case-Control Studies; D017115:Catheter Ablation; D005240:Feasibility Studies; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011667:Pulmonary Veins / Q000601:surgery*