title: Characteristics of atrial tachycardia due to small vs large reentrant circuits after ablation of persistent atrial fibrillation.
abstract: BACKGROUND
  While macroreentrant atrial tachycardias (ATs) have been reasonably well described, little is known about small reentrant circuits.
  
  
  OBJECTIVE
  To compare characteristics of large and small reentrant circuits after ablation of persistent atrial fibrillation.
  
  
  METHODS
  Seventy-seven patients (age 61±10 years; left atrium 46±6 mm; ejection fraction 0.52±0.13) underwent a procedure for postablation AT. The p-wave duration, circuit size, electrogram characteristics, and conduction velocity were determined.
  
  
  RESULTS
  AT was due to macroreentry in 62 (80%) patients, a small reentrant circuit in 13 (17%), and a focal mechanism in 2 (3%). The p-wave duration during small reentrant ATs was shorter than that during macroreentry (174±12 ms vs 226±22 ms; P<.0001). The duration of fractionated electrograms at the critical site was longer in small vs large circuits (167±43 ms vs 98±38 ms, respectively; P<.0001) and accounted for a greater percentage of the tachycardia cycle length (59%±18% vs 38%±14%, respectively; P<.0001). The mean diameters of macroreentrant and small reentrant circuits were 44±7 and 26±11 mm, respectively (P<.0001). The mean conduction velocity along the small circuits was lower (0.5±0.2 m/s vs 1.2±0.3 m/s; P<.0001). Catheter ablation eliminated the AT in all 77 patients.
  
  
  CONCLUSIONS
  AT due to a small reentrant circuit after ablation of atrial fibrillation may be distinguished from macroreentry by a shorter p-wave duration and the presence of long-duration electrograms at the critical site owing to extremely slow conduction. These features may aid the clinician in the mapping of postablation ATs.
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109-5853, USA.
authors.forename: Miki
authors.initials: M
authors.lastname: Yokokawa
authors.forename: Rakesh
authors.initials: R
authors.lastname: Latchamsetty
authors.forename: Hamid
authors.initials: H
authors.lastname: Ghanbari
authors.forename: Diego
authors.initials: D
authors.lastname: Belardi
authors.forename: Akash
authors.initials: A
authors.lastname: Makkar
authors.forename: Brett
authors.initials: B
authors.lastname: Roberts
authors.forename: Wouter
authors.initials: W
authors.lastname: Saint-Phard
authors.forename: Mohamad
authors.initials: M
authors.lastname: Sinno
authors.forename: Thomas
authors.initials: T
authors.lastname: Carrigan
authors.forename: Robert
authors.initials: R
authors.lastname: Kennedy
authors.forename: Arisara
authors.initials: A
authors.lastname: Suwanagool
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Thomas
authors.initials: T
authors.lastname: Crawford
authors.forename: Krit
authors.initials: K
authors.lastname: Jongnarangsin
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D018780:Body Surface Potential Mapping / Q000379:methods; D017115:Catheter Ablation / Q000379:methods*; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis; D012372:ROC Curve; D012008:Recurrence; D018570:Risk Assessment; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology; D015996:Survival Rate; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis* / Q000453:epidemiology; D016896:Treatment Outcome