title: Effect of atrial fibrillation duration on probability of immediate recurrence after transthoracic cardioversion.
abstract: BACKGROUND
  An immediate recurrence of atrial fibrillation (IRAF) appears to be more common after early restoration of sinus rhythm with an implantable atrial defibrillator than after elective transthoracic cardioversion, which suggests that the probability of IRAF may be related to the duration of AF.
  
  
  RESULTS
  Transthoracic cardioversion was performed 85 +/- 187 days (range 7 minutes to 8 years) after the onset of atrial fibrillation in 315 patients (mean age 61 +/- 13 years). IRAF was defined as a recurrence of AF within 60 seconds after restoration of sinus rhythm. IRAF occurred in 56% of patients when cardioversion was performed within 1 hour of the onset of AF compared with 12% of patients when cardioversion was performed after 24 hours of AF (P < 0.001). The duration of AF was the only independent predictor of IRAF among the clinical variables of age, gender, structural heart disease, antiarrhythmic drug therapy, and cardioversion energy (P < 0.01).
  
  
  CONCLUSIONS
  IRAF is more likely to occur when the duration of AF is <1 hour than when the duration is >24 hours. This observation has clinical implications for the most appropriate timing of cardioversion, particularly in patients who receive device therapy for AF.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109-0311, USA. oralh@umich.edu
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ozaydin
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tada
authors.forename: Christoph
authors.initials: C
authors.lastname: Scharf
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Steve W K
authors.initials: SW
authors.lastname: Lai
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Knight
authors.forename: S Adam
authors.initials: SA
authors.lastname: Strickberger
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy*; D004554:Electric Countershock / Q000379:methods*; D004562:Electrocardiography; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D012008:Recurrence; D013223:Statistics as Topic; D017211:Treatment Failure; D014481:United States / Q000453:epidemiology