title: Electrogram polarity reversal as an additional indicator of breakthroughs from the left atrium to the pulmonary veins.
abstract: OBJECTIVE
  We assessed the anatomical distribution and electrogram characteristics of breakthrough from the left atrium (LA) to the pulmonary veins (PVs).
  
  
  BACKGROUND
  Localization of LA-PV breakthrough is an important technique for PV ablation in patients with atrial fibrillation (AF).
  
  
  METHODS
  A total of 157 patients with paroxysmal AF underwent PV disconnection guided by mapping with a circumferential 10-electrode catheter. Radiofrequency (RF) current was delivered ostially at the site(s) of earliest activation (113 patients) or electrogram polarity reversal defined by opposite polarity across adjacent bipoles (44 patients). Breakthrough sites were proved by changes in pulmonary vein potential activation sequence occurring as a result of localized RF delivery and were classified into four segments around the ostium (top, bottom, anterior, posterior). Results of mapping and ablation were compared between the two groups.
  
  
  RESULTS
  A total of 99% of 411 targeted PVs were successfully disconnected in both groups. Breakthroughs were most frequent at the bottom of superior PVs (85% prevalence) and the top of inferior PVs (75% prevalence). A wide activation front (>5 synchronous bipoles) indicating broad breakthrough was observed in 18% of PVs. Polarity reversal occurred with 88% sensitivity and 91% specificity at breakthrough sites. Polarity reversal was restricted to fewer bipoles (2.0 +/- 0.4 bipoles vs. 3.4 +/- 2.0 bipoles, p < 0.01) compared with earliest activation. Shorter RF application time was required to disconnect PVs with wide synchronous activation using polarity reversal compared with using conventional earliest activity (10.3 +/- 3.0 min vs. 12.3 +/- 3.4 min, p < 0.05).
  
  
  CONCLUSIONS
  Bipolar electrogram polarity reversal allows more precise localization of breakthrough compared with the earliest activation, particularly in cases of wide synchronous PV activation.
authors.affiliation: Hôpital Cardiologique du Haut-Lévêque, Bordeaux-Pessac, France. jacques.clementy@pu.u-bordeaux2.fr
authors.forename: Teiichi
authors.initials: T
authors.lastname: Yamane
authors.forename: Dipen C
authors.initials: DC
authors.lastname: Shah
authors.forename: Pierre
authors.initials: P
authors.lastname: Jaïs
authors.forename: Mélèze
authors.initials: M
authors.lastname: Hocini M
authors.forename: Isabel
authors.initials: I
authors.lastname: Deisenhofer
authors.forename: Kee-Joon
authors.initials: KJ
authors.lastname: Choi
authors.forename: Laurent
authors.initials: L
authors.lastname: Macle
authors.forename: Jacques
authors.initials: J
authors.lastname: Clémenty
authors.forename: Michel
authors.initials: M
authors.lastname: Haïssaguerre
mesh_terms: D000328:Adult; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology* / Q000601:surgery; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D011667:Pulmonary Veins / Q000503:physiopathology* / Q000601:surgery; D012008:Recurrence; D012680:Sensitivity and Specificity; D013997:Time Factors