title: Factors influencing immediate and long-term outcome of electrical cardioversion of persistent atrial fibrillation and flutter.
abstract: BACKGROUND
  To investigate which factors influence the immediate and long-term outcome of elective electrical cardioversion for persistent (>48h) atrial fibrillation or flutter.
  
  
  METHODS
  In 255 patients, 435 electrical cardioversions were performed. Relevant clinical, electrocardiographic and echocardiographic factors were registered at each cardioversion. Each factor was tested separately in relation to immediate success and the outcome at six months and one year after cardioversion.
  
  
  RESULTS
  In 70% of the patients, sinus rhythm was restored immediately after electrical cardioversion. After six months only 20% of the patients were still in sinus rhythm, and one year after cardioversion this figure had dropped to 14%. Sotalol used during electrical cardioversion resulted in the highest immediate success. Furthermore, atrial flutter, two or fewer electrical shocks and shocks ≤200 Joules resulted in the highest immediate success rate, whilst hypertensive heart disease resulted in the lowest immediate success rate. However, only shocks ≤200 Joules and a first cardioversion promoted the persistence of sinus rhythm after six months. A normal electrocardiogram, two or more cardioversions in the past and the use of a beta-blocking drug other than sotalol during cardioversion increased the chance of recurrence within six months. The duration of the arrhythmia >one month to <one year before the cardioversion and a first cardioversion resulted in the least recurrences one year after cardioversion. A QTc <450 msec, shocks >200 Joules and more than two cardioversions in the past were associated with a high number of recurrences one year later. With multivariate analysis we found that atrial flutter, low energy levels, low number of shocks and a long QTc-interval influence the immediate success positively. However, no factor influenced the persistence of sinus rhythm at six months and one year.
  
  
  CONCLUSIONS
  In patients with persistent atrial fibrillation or flutter, only about 15% are in sinus rhythm one year after attempted cardioversion. Atrial fibrillation rather than flutter, high energy shocks and previous cardioversions negatively influenced the immediate success of cardioversion. However, none of the clinical, electrocardiographic or echocardiographic baseline factors studied could be identified as playing a role in the prediction of long-term sinus rhythm.
authors.forename: S
authors.initials: S
authors.lastname: Tabery
authors.forename: L
authors.initials: L
authors.lastname: Bouwels
authors.forename: G J H
authors.initials: GJ
authors.lastname: Uijen
authors.forename: A
authors.initials: A
authors.lastname: Uppelschoten
authors.forename: F W A
authors.initials: FW
authors.lastname: Verheugt
keywords: atrial fibrillation; atrial flutter; electrical cardioversion; follow-up; success