title: Electrophysiological characteristics of localized reentrant atrial tachycardia occurring after catheter ablation of long-lasting persistent atrial fibrillation.
abstract: BACKGROUND
  Mapping of recurrent atrial tachycardia (AT) after extensive ablation for long-lasting persistent atrial fibrillation (AF) is complex. We sought to describe the electrophysiological characteristics of localized reentry occurring after ablation of long-lasting persistent AF.
  
  
  METHODS
  Out of 70 patients undergoing catheter ablation of long-lasting persistent AF, 9 patients (13%, 55 +/- 8 years, 8 males) in whom localized reentry was demonstrated in a repeat ablation were studied. Localized reentry was defined as reentry in which the circuit was localized to a small area and did not have a central obstacle. The mechanism of AT was determined by electroanatomical and entrainment mapping.
  
  
  RESULTS
  Nine localized reentries with cycle length of 243 +/- 41 ms were mapped in 9 patients. The location of AT was the left atrial appendage in 4 patients, anterior left atrium in 2, left septum in 2, and mitral isthmus in 1. In all ATs, a critical isthmus of <10 mm in width was identified in the vicinity of the prior linear lesions or ostia of isolated pulmonary veins. Ablation of the critical isthmus, which was characterized by continuous low-voltage activity (median voltage: 0.15 mV, mean duration: 117 +/- 31 ms), terminated AT and rendered it noninducible. Additionally, ablation was performed for all of inducible ATs. At 11 +/- 7 months after the procedure, 8 of 9 patients (89%) were free from any arrhythmias.
  
  
  CONCLUSIONS
  After ablation of long-lasting persistent AF, localized reentry may arise from a site in the vicinity of the prior ablation lesions. Ablation of the critical isthmus eliminates the arrhythmia.
authors.affiliation: From the Cardiovascular Center, Yokosuka Kyousai Hospital, Yonegahama-dori 1-16,Yokosuka, Kanagawa, Japan. yoshihide_takahashi@oboe.ocn.ne.jp
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Taishi
authors.initials: T
authors.lastname: Kuwahara
authors.forename: Asumi
authors.initials: A
authors.lastname: Takei
authors.forename: Tadashi
authors.initials: T
authors.lastname: Fujino
authors.forename: Akira
authors.initials: A
authors.lastname: Fujii
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kusa
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Yagishita
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nozato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hikita
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hirao
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000209:etiology* / Q000601:surgery*; D013612:Tachycardia, Ectopic Atrial; D016896:Treatment Outcome