title: Prevalence and significance of focal sources of atrial arrhythmia in patients undergoing cardioversion of persistent atrial fibrillation.
abstract: BACKGROUND
  Recent reports have high-lighted the importance of focal atrial arrhythmias as a curable cause for a group of patients with frequently recurrent paroxysmal atrial fibrillation (AF). The importance of this arrhythmia mechanism in the general population of patients with persistent AF is unknown.
  
  
  RESULTS
  After successful internal cardioversion of 50 consecutive patients with persistent AF (mean age 60 years, mean duration of AF 26 months), endocardial activity in the immediate postcardioversion period was analyzed for the presence of focal atrial activity. Postcardioversion atrial arrhythmias were considered to be focal if there was evidence of a localized source of repetitive early atrial activation, either in the form of (1) self-terminating monomorphic atrial tachycardia (at least five beats) or (2) recurrences of AF with an initial atrial activation sequence (first five beats) that was both monomorphic and reproducible with repeated recurrences. Evidence for a focal atrial arrhythmia was present in 20 of the total group of 50 patients (40%). Multivariate analysis of clinical characteristics revealed the diagnosis of lone AF as the only independent predictor of a focal source of AF (P = 0.028). Thirty-nine patients were discharged from hospital in sinus rhythm. At 1-month follow-up, 25 (64%) of these 39 patients had suffered AF recurrence. The only significant predictor of AF recurrence was evidence of a focal source of atrial arrhythmia immediately after cardioversion, with a relative risk of 1.73 (range 1.1 to 2.7; P = 0.015).
  
  
  CONCLUSIONS
  Focal atrial arrhythmias are common in patients presenting with "idiopathic" persistent AF, suggesting a possible causative role in the generation of this common arrhythmia.
authors.affiliation: Manchester Heart Centre, Manchester Royal Infirmary, United Kingdom.
authors.forename: D M
authors.initials: DM
authors.lastname: Todd
authors.forename: S P
authors.initials: SP
authors.lastname: Fynn
authors.forename: W J
authors.initials: WJ
authors.lastname: Hobbs
authors.forename: A P
authors.initials: AP
authors.lastname: Fitzpatrick
authors.forename: C J
authors.initials: CJ
authors.lastname: Garratt
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology* / Q000628:therapy*; D016275:Atrial Function; D004554:Electric Countershock; D004699:Endocardium / Q000503:physiopathology; D005260:Female; D006325:Heart Atria; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D012008:Recurrence; D013610:Tachycardia / Q000150:complications* / Q000453:epidemiology* / Q000503:physiopathology