title: Isolation of pulmonary veins using a transvenous curvilinear cryoablation catheter: feasibility, initial experience, and analysis of recurrences.
abstract: BACKGROUND
  Pulmonary vein isolation (PVI) using focal cryothermal catheters is safe and moderately effective, but associated with long procedure times. We hypothesized that a linear freezing segment could shorten fluoroscopic and procedure times. We report our initial experience with a novel circular cryothermal catheter.
  
  
  RESULTS
  Complete PV isolation (PVI) was achieved in 41 of 45 PVs by cryoablation (91%) in 18 patients who underwent Lasso-guided cryothermal using a novel 7 F circular catheter (2.5 +/- 0.7 veins per patient). A mean of 27.2 +/- 11 applications per patient (9.2 +/- 4.7 per vein) with a mean temperature -79.8 +/- 4 degrees C were delivered. Recorded temperatures did not predict complete or incomplete isolation. Focal cryothermal ablation using a 7 F 4-mm tip was required in the remainder for isolation. During 14.8 +/- 6.2 month follow-up, 4 (22%) had no recurrence of AF, and 7/18 (39%) had >90% reduction in symptoms without antiarrhythmic agents (AAA). Computed tomography scans at 3 months showed no stenosis (14.1 +/- 2.5 mm, 13.9 +/- 2.4 mm; P = 0.2). Eight patients underwent repeat ablation. Mapping demonstrated 13 of 14 (93%) previously isolated veins had recovery of over 64 +/- 24% of the ostium. All were successfully isolated with RF and 7 of 8 were arrhythmia free 6.0 +/- 2.9 months after ablation. Overall, 14 of 18 (78%) patients had their arrhythmia clinically controlled without drugs after one or two procedures.
  
  
  CONCLUSIONS
  Our initial experience demonstrates safety and feasibility of circular cryothermal ablation with less fluoroscopic and procedure times as compared to focal cryothermy. As with RF, complete and permanent isolation of the PVs is not easily achieved. Reducing heat load due to PV flow may improve results.
authors.affiliation: Arrhythmia Service, London Health Sciences Centre, University of Western Ontario, London, Ontario, Canada. allan.skanes@lhsc.on.ca
authors.forename: Allan C
authors.initials: AC
authors.lastname: Skanes
authors.forename: Steen M
authors.initials: SM
authors.lastname: Jensen
authors.forename: Robert
authors.initials: R
authors.lastname: Papp
authors.forename: Juliana
authors.initials: J
authors.lastname: Li
authors.forename: Raymond
authors.initials: R
authors.lastname: Yee
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Krahn
authors.forename: George J
authors.initials: GJ
authors.lastname: Klein
mesh_terms: D001281:Atrial Fibrillation / Q000628:therapy*; D017115:Catheter Ablation / Q000379:methods*; D017679:Cryotherapy; D004594:Electrophysiology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011667:Pulmonary Veins; D012008:Recurrence; D012449:Safety; D013997:Time Factors