HAMILTON, CANADA. Current guidelines for the management of atrial fibrillation (AF) recommend first-line treatment with antiarrhythmics. However, the efficacy of antiarrhythmics such as sotalol, propafenone, and flecainide in preventing recurrence over a one-year period is only about 50% or less. Amiodarone is somewhat more effective (prevents recurrence in about 65% of cases), but comes with serious potential side effects. Researchers at McMaster University now report on a study to determine the relative efficacy of radiofrequency (RF) ablation and treatment with antiarrhythmics.
Their study involved a meta-analysis of 6 randomized trials comparing RF ablation with antiarrhythmic mediations in the treatment of AF. About two-thirds of the patients involved in the trials had structural heart disease and most had paroxysmal or persistent afib. Most of the trials were performed at high volume centers, with expert operators performing the ablations. A total of 348 patients were assigned to receive antiarrhythmics (sotalol, class I agents or amiodarone), while 345 were assigned to undergo a PVI followed by linear ablation and ablation of fractionated electrograms as appropriate. Touch-up procedures were allowed within the blanking period of the trials (first 2 to 3 months after ablation).
At the end of the one-year follow-up period, only 27% of the drug-treated patients were still in sinus rhythm as compared to 76% in the ablation group – a relative risk reduction for recurrence of 65% for ablation vs. drug treatment. The researchers suggest that their findings raise a couple of interesting questions:
Nair, GM, et al. A systematic review of randomized trials comparing radiofrequency ablation with antiarrhythmic medications in patients with atrial fibrillation. Journal of Cardiovascular Electrophysiology, September 3, 2008 [Epub ahead of print] Editor's comment
- Should we wait for patients to fail antiarrhythmic medications before recommending catheter ablation?
- Is it possible that catheter ablation as a first-line treatment for AF will yield better results?
: It should be kept in mind that the above conclusions may not necessarily apply to lone afibbers. Class I drugs (flecainide, propafenone, disopyramide) can be quite effective in lone afibbers, but afib patients with underlying heart disease they may be dangerous. Thus, sotalol and amiodarone are the primary antiarrhythmics used among AF patients with underlying heart disease. The benefits of antiarrhythmics were evaluated in LAF Surveys 2 and 14. Class I drugs were found effective by about 55% of users in Survey 2 and by about 40% in Survey 14. Amiodarone was found effective by about 65% and sotalol by 32% in Survey 14. In considering the results of the meta-analysis, it should also be kept in mind that the ablations were performed by highly skilled operators. Personally, I would think that there would be little difference in efficacy between treatment with antiarrhythmics and ablations carried out by less experienced EPs.