RAAFT-2 Published, but Editorial Says No Changes in AF Guidelines

February 18, 2014

HAMILTON, ON – The Radiofrequency Ablation vs Antiarrhythmic Drugs as First-Line Therapy of Atrial Fibrillation (RAAFT 2) trial, a study that showed radiofrequency catheter ablation with pulmonary-vein isolation could be successfully performed as first-line therapy in patients with atrial fibrillation (AF), is now published[1].

First presented at the Heart Rhythm Society 2012 Scientific Sessions, the study is now in the February 19, 2014 issue of the Journal of the American Medical Association.

For Dr Hugh Calkins (Johns Hopkins University Medical Center, Baltimore, MD), who wrote an editorial accompanying the RAAFT-2 paper[2], the results are important to help define the efficacy, safety, and appropriate role of catheter ablation in patients with AF. Most important, when the results are analyzed with other data, the study reinforces the conclusion that AF ablation for most patients is not a curative procedure.

This trial and others "make it clear that symptomatic and asymptomatic recurrences of AF are not uncommon following AF ablation and that the efficacy of this procedure, even in optimal candidates, is modest," writes Calkins.

As reported previously by heartwire , the RAAFT-2 study investigators, led by Dr Carlos Morillo (McMaster University, Hamilton, ON), showed that 54.5% of patients with persistent or paroxysmal AF treated with first-line ablation therapy experienced a documented atrial tachyarrhythmia lasting more than 30 seconds over the 24-month follow-up period. In comparison, 72.1% of patients treated with antiarrhythmic medication experienced an atrial tachyarrhythmia. This translated into a 44% lower risk of symptomatic or asymptomatic AF, atrial flutter, or atrial tachycardia over the two-year period. Recurrent arrhythmias were documented by electrocardiogram, Holter, transtelephonic monitor, or rhythm strip.

Regarding secondary end points in the 127-patient trial conducted at 16 centers in Europe and North America, 59% of patients treated with antiarrhythmic medication had a recurrence of symptomatic AF, atrial flutter, or atrial tachycardia at two years compared with 47% of patients treated with first-line catheter ablation therapy. There were no deaths or stroke in the ablation arm, but four cases of cardiac tamponade were documented. Quality of life was improved with both treatments.

Ablation Not Without Risks

The RAAFT-2 results, according to Calkins, should remind electrophysiologists that ablation is not without its risks. The overall complication rate in the trial was 9%, and the rate of cardiac tamponade was 6%. These rates are higher than those reported in a recent worldwide survey of AF-ablation procedures, Calkins notes, and lower rates would have been expected given the experience of the operators and the relative health of the patients.

To Calkins, RAAFT-2 reinforces the recommendations of the 2012 Heart Rhythm Society/European Heart Rhythm Association/ European Cardiac Arrhythmia Society consensus statement and the 2012 European Society of Cardiology updated atrial-fibrillation guidelines. Catheter ablation is class 1 recommendation (A level of evidence) in patients with paroxysmal AF who have failed at least one antiarrhythmic drug. It is only a class 2 recommendation (B level of evidence) for paroxysmal AF patients who have not yet failed drug therapy.

"In clinical practice, it is uncommon to find a patient who is eager to undergo catheter ablation without at least one trial of an antiarrhythmic medication," writes the editorialist. "This is especially true after a thorough discussion of the risks of the procedure, the fact that 30% to 50% of patients require a repeat procedure, and consideration that the techniques and tools used for catheter ablation continue to improve."

The one subgroup of patients that might benefit from immediate ablation of AF comprises those with paroxysmal AF and significant sinus-node dysfunction, according to Calkins. The data suggest the procedure can help control AF and eliminate the need for a pacemaker in this patient subgroup.

This study was supported by an unrestricted research grant from BiosenseWebster and the Population Health Research Institute (PHRI), sponsored and supported by PHRI at McMaster University. Morillo reported receiving grants from Biosense Webster, Boston Scientific, Medtronic, and St Jude Medical and consulting fees from Biosense Webster, Boston Scientific, Biotronik, Boehringer Ingelheim, and Merck. Disclosures for the coauthors are listed in the paper. Calkins has no conflicts of interest.

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