title: Rapid ablation for atrial flutter by targeting maximum voltage-factors associated with short ablation times.
abstract: BACKGROUND
  The maximum voltage-guided (MVG) approach to ablation for atrial flutter targets high-amplitude signals along the cavotricuspid isthmus (CTI). It is based on the observation that the isthmus is often composed of bundles of conducting tissue and the hypothesis that these bundles manifest as high-amplitude electrograms, providing targets for selective ablation. We aim to identify patient and procedural factors that correlate with rapid isthmus ablation.
  
  
  METHODS
  All patients undergoing CTI ablation at our center from January 2005 to May 2006 were included. Patients were divided into outcome groups relative to the median value for total ablation time. The two groups were compared according to patient and procedural variables, using multivariate regression methods.
  
  
  RESULTS
  Seventy-six patients were assessed with mean age 60.2 +/- 10.6 years; 63 (82.9%) were male. Mean ablation time to bidirectional block across the CTI was 6.85 +/- 5.87 min (range 0.68-28.7); median 4.77 min. Seventy-six percent of patients required less than 5 min total ablation time until bidirectional block was achieved. Variables independently associated with a short ablation time were the presence of sinus rhythm at start of ablation (P = 0.0050, odds ratio (OR) 8.03), high mean temperature among all ablations (P = 0.019, OR 17.81), and low variability of mean power among all ablations (P = 0.0048, OR 19.26).
  
  
  CONCLUSIONS
  Using the MVG approach to atrial flutter ablation, shorter total ablation times are observed among patients in sinus rhythm at the onset of ablation, with higher mean temperature among ablation lesions, and less variability of power between ablations.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Western Ontario, London, Ontario, Canada.
authors.forename: Rajesh N
authors.initials: RN
authors.lastname: Subbiah
authors.forename: Lorne J
authors.initials: LJ
authors.lastname: Gula
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Krahn
authors.forename: Emoke
authors.initials: E
authors.lastname: Posan
authors.forename: Raymond
authors.initials: R
authors.lastname: Yee
authors.forename: George J
authors.initials: GJ
authors.lastname: Klein
authors.forename: Allan C
authors.initials: AC
authors.lastname: Skanes
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012008:Recurrence; D012044:Regression Analysis; D013997:Time Factors; D016896:Treatment Outcome