title: Acute effects of left atrial radiofrequency ablation on atrial fibrillation.
abstract: BACKGROUND
  Acutely, when left atrial ablation is performed during atrial fibrillation (AF), the AF may persist and require cardioversion, or it may convert to sinus rhythm or to atrial tachycardia/flutter. The prevalence of these acute outcomes has not been described.
  
  
  RESULTS
  Left atrial ablation, usually including encirclement of the pulmonary veins, was performed during AF in 144 patients with drug-refractory AF. Conversion to sinus rhythm occurred in 19 patients (13%), to left atrial tachycardia in 6 (4%), and to atrial flutter in 6 (4%). In the 6 patients with a focal atrial tachycardia, the mean cycle length was 294 +/- 45 ms. The tachycardia arose in the left atrial roof in 3 patients, the left atrial appendage in 2, and the anterior left atrium in 1. In 3 of 6 patients, the focal atrial tachycardia originated in an area that displayed a relatively short cycle length during AF. In 6 patients, AF converted to macroreentrant atrial flutter with a mean cycle length of 253 +/- 47 ms, involving the mitral isthmus in 5 patients and the septum in 1 patient. All atrial tachycardias and flutters were successfully ablated with 1 to 15 applications of radiofrequency energy.
  
  
  CONCLUSIONS
  When left atrial ablation is performed during AF, the AF may convert to atrial tachycardia or flutter in approximately 10% of patients. Focal atrial tachycardias that occur during ablation of AF may be attributable to driving mechanisms that persist after AF has been eliminated, whereas atrial flutter results from incomplete ablation lines.
authors.affiliation: Division of Cardiology, University of Michigan, Ann Arbor 48109-0022, USA.
authors.forename: Christoph
authors.initials: C
authors.lastname: Scharf
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Burr
authors.initials: B
authors.lastname: Hall
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Peter
authors.initials: P
authors.lastname: Cheung
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D001282:Atrial Flutter / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000503:physiopathology / Q000601:surgery; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D016896:Treatment Outcome