Worldwide survey on ablation efficacy
MILAN, ITALY. A group of prominent electrophysiologists has updated their 2005 worldwide survey of the efficacy and safety of catheter ablation for atrial fibrillation (AF). The 2005 survey covered the years 1995 to 2002 and involved 8,745 patients treated in 90 centers. The new 2010 survey covers the years 2003 to 2006 and involves 16,309 patients treated in 90 centers. The final complete success rate (no AF, no antiarrhythmics) in the 2005 survey was 52% vs. 64.3% in the 2010 survey. The partial success rate (no AF, but only with the aid of previously unsuccessful antiarrhythmics) was 23.9% in the 2005 survey and 12.5% in the 2010 survey, so the combined final success rate (after an average of 1.3 procedures per patient) was 76% in the 2005 survey and 77% in the 2010 survey. After removing data from centers with the least and the most experience, complete success rate was 70% and partial success rate was 10%. Other highlights from the 2010 survey:

  • Anatomically-guided circumferential ablation (CARTO) has replaced the Lasso-guided segmental procedure as the most popular. In the 2010 survey 48.2% were treated with the circumferential procedure vs. 27.4% for the segmental procedure. The success rates for the two procedures were similar; however, the incidence of atrial flutter resulting from the procedure (iatrogenic flutter) was 8 times higher in centers using exclusively CARTO-guided ablation than in centers using exclusively Lasso-guided ablation (14.3% vs. 1.8%).
  • More than 98% of procedures used radio frequency energy in lesion creation and a cooled or irrigated catheter was used in 70% of cases.
  • While all centers performed ablations for paroxysmal AF in both the 2005 and the 2010 surveys, the number of centers performing procedures for persistent and permanent AF increased from 53% to 86% and from 20% to 47% respectively.
  • Most (95%) of centers required patients to have failed at least one antiarrhythmic drug before accepting them for ablation. However, more centers accepted patients with an enlarged left atrium, reduced left ventricular ejection fraction, and prior heart surgery in the 2010 survey.
  • The odds of having a successful procedure were substantially less in patients with persistent or permanent AF.
  • The odds of having a successful procedure (no AF, no antiarrhythmics) increased markedly with the number of procedures performed per center. The increase in success rate was found to be 4% for each additional 30 procedures performed.
  • A major complication occurred in 741 patients (4.5%). There were 25 procedure-related deaths (0.15%), 152 strokes or transient ischemic attacks [TIAs] (0.94%), and 213 tamponades (1.31%). Six patients (0.04%) experienced an atrioesophageal fistula (71% fatal), while 48 patients (0.29%) experienced pulmonary vein stenosis serious enough to warrant surgical intervention.
The authors of the study conclude with the caveat, "The variability in monitoring methods and their accuracy together with the intensity of monitoring inherently limit interpretation of data coming from a large survey. Based on this observation, it is possible that freedom of all AF episodes in the investigated population was 10% to 20% lower than that reported in this analysis."

Cappato, R, et al. Updated worldwide survey on the methods, efficacy, and safety of catheter ablation for human atrial fibrillation. Circulation Arrhythmia and Electrophysiology, Vol. 3, February 2010, pp. 32-38

Editor's comment: The results of our 2008 ablation/maze survey are in line with those reported in the latest Cappato survey. Average final complete success rate (no AF, no antiarrhythmics) was 47% for the period 1998 to 2004 (corresponding Cappato number for 1995 to 2002 was 52%) and 66% for the period 2007 to 2008 (Cappato number for 2003 to 2006 was 64.3%).