title: Pulmonary vein isolation: comparison of bipolar and unipolar electrograms at successful and unsuccessful ostial ablation sites.
abstract: BACKGROUND
  No prior studies have quantitatively analyzed the characteristics of bipolar or unipolar electrograms that may be helpful in identifying successful ostial ablation sites in patients with atrial fibrillation undergoing segmental pulmonary vein isolation.
  
  
  RESULTS
  The characteristics of bipolar and unipolar electrograms recorded at 185 successful and 120 unsuccessful ostial pulmonary venous ablation sites were analyzed in 21 patients with atrial fibrillation. A decapolar Lasso catheter was positioned near the ostia of the pulmonary veins, and a conventional ablation catheter was used to deliver radiofrequency energy at individual ostial sites where pulmonary vein potentials were recorded. With both bipolar and unipolar recordings, the only timing parameter that distinguished successful from unsuccessful ostial ablation sites was the timing of the electrogram recorded by the ablation catheter relative to the earliest pulmonary vein potential recorded by the Lasso catheter. With both bipolar and unipolar recordings, electrograms demonstrated a larger amplitude at successful than at unsuccessful ablation sites. Unipolar electrograms had a steeper intrinsic deflection at successful than at unsuccessful ostial ablation sites. The morphologies of the unipolar electrograms recorded by the ablation catheter and by the contiguous electrode of the Lasso catheter usually were identical.
  
  
  CONCLUSIONS
  In patients undergoing segmental isolation of the pulmonary veins, unipolar recordings provide more information than bipolar recordings helpful in distinguishing successful from unsuccessful ostial ablation sites. Furthermore, unipolar recordings, but not bipolar recordings, allow accurate localization of the position of the ablation catheter relative to the electrodes of the Lasso catheter.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0022, USA.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tada
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Kristina
authors.initials: K
authors.lastname: Wasmer
authors.forename: Radmira
authors.initials: R
authors.lastname: Greenstein
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Knight
authors.forename: S Adam
authors.initials: SA
authors.lastname: Strickberger
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000503:physiopathology; D017115:Catheter Ablation / Q000295:instrumentation; D004562:Electrocardiography; D004568:Electrodiagnosis; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000033:anatomy & histology / Q000502:physiology*; D017211:Treatment Failure