title: The duration of atrial fibrillation influences the long-term efficacy of low-energy internal cardioversion.
abstract: BACKGROUND
  It is commonly held that long-lasting atrial fibrillation (AF), especially if associated with marked enlargement of the left atrium, is a negative predictive factor for both the recovery and the maintenance of sinus rhythm. The aim of the present study was to identify the clinical features of patients who have a greater likelihood of success both in the acute phase and, especially, in the medium-long term.
  
  
  METHODS
  Since June 1997, we have performed low-energy internal cardioversion to 93 patients (66 males, 27 females, mean age 62 +/- 9 years, range 26-80 years) with a mean duration of AF of 922 +/- 1032 days. Seventy-four patients had heart disease and 19 isolated AF. External cardioversion had been previously performed in 79 patients to no avail. All patients underwent antiarrhythmic therapy and were followed for a period of 13 +/- 7 months.
  
  
  RESULTS
  Low-energy internal cardioversion proved efficacious, restoring sinus rhythm, in 92% of patients (86/93) and inefficacious in 8% (7/93). In 24% (21/86) the procedure, although efficacious, was followed by early recurrence of AF which proved to be intractable in 52% (11/21). At the end of the session, 81% (75/93) of the patients maintained sinus rhythm. At the end of follow-up, 40% (38/93) maintained sinus rhythm. Of all the parameters considered in the two groups, the duration of AF was the only one which differed significantly between the group in sinus rhythm and that in AF, with regard to both the efficacy of the procedure in the acute phase (755 +/- 868 vs 1618 +/- 1359 days, p < 0.001) and the long-term outcome (655 +/- 5.8 vs 1107 +/- 1098 days, p < 0.05).
  
  
  CONCLUSIONS
  AF lasting more than 2 years constitutes a negative predictive factor for both the recovery and the long-term maintenance of sinus rhythm.
authors.affiliation: Cardiology Unit, Civil Hospital of Conegliano, TV. leocoro@libero.it
authors.forename: L
authors.initials: L
authors.lastname: Corò
authors.forename: P
authors.initials: P
authors.lastname: Delise
authors.forename: E
authors.initials: E
authors.lastname: Bertaglia
authors.forename: M G
authors.initials: MG
authors.lastname: Mozzato
authors.forename: M
authors.initials: M
authors.lastname: Fantinel
authors.forename: G
authors.initials: G
authors.lastname: Bilardo
authors.forename: D
authors.initials: D
authors.lastname: D'Este
authors.forename: P
authors.initials: P
authors.lastname: Pascotto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000628:therapy*; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012008:Recurrence; D013995:Time; D016896:Treatment Outcome