title: Prevalence, mechanisms, and clinical significance of macroreentrant atrial tachycardia during and following left atrial ablation for atrial fibrillation.
abstract: OBJECTIVE
  The purpose of this study was to determine the prevalence and clinical significance of macroreentrant atrial tachycardia (AT) after left atrial (LA) circumferential ablation for atrial fibrillation (AF).
  
  
  BACKGROUND
  Linear ablation for AF may result in macroreentrant AT.
  
  
  METHODS
  Three hundred forty-nine patients (age 54 +/- 11 years) underwent LA circumferential ablation for AF (paroxysmal in 227). Ablation lines were created around the left-sided and right-sided pulmonary veins, with additional ablation lines in the posterior LA and mitral isthmus. If macroreentrant AT was observed acutely in the electrophysiology laboratory, it was not ablated. If an organized AT occurred during follow-up, the initial strategy was rate control. If AT persisted for > 3 to 4 months, catheter ablation was performed.
  
  
  RESULTS
  Seventy-one patients (20%) had spontaneous or induced macroreentrant AT (cycle length 244 +/- 31 ms) in the electrophysiology laboratory following LA circumferential ablation. During follow-up, 85 patients (24%) experienced spontaneous AT (cycle length 238 +/- 35 ms) at a mean of 44 +/- 62 days following LA circumferential ablation. Among the 71 patients with macroreentrant AT acutely following LA circumferential ablation, 39 (55%) developed AT during follow-up. Among the 85 patients with AT during follow-up, the tachycardia remitted without a repeat ablation procedure in 28 patients (33%), most commonly within 5 months. Twenty-eight of the 349 patients (8%) underwent a repeat ablation procedure for AT. The critical isthmus was localized to the mitral isthmus in 17 of 28 patients (61%).
  
  
  CONCLUSIONS
  Macroreentrant AT is a common form of proarrhythmia after LA circumferential ablation for AF. Because it may resolve spontaneously, ablation of AT should be deferred for several months.
authors.affiliation: Division of Cardiology, University of Michigan Hospitals, Ann Arbor, Michigan 48109-0311, USA. achugh@umich.edu
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Kristina
authors.initials: K
authors.lastname: Lemola
authors.forename: Burr
authors.initials: B
authors.lastname: Hall
authors.forename: Peter
authors.initials: P
authors.lastname: Cheung
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Kamala
authors.initials: K
authors.lastname: Tamirisa
authors.forename: Jihn
authors.initials: J
authors.lastname: Han
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
mesh_terms: D001281:Atrial Fibrillation / Q000628:therapy*; D017115:Catheter Ablation / Q000009:adverse effects*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000601:surgery; D013612:Tachycardia, Ectopic Atrial / Q000209:etiology* / Q000503:physiopathology