domingo, 4 de janeiro de 2009

Ablation superior to antiarrhythmic drugs in paroxysmal AF

MedWire News: The A4 trial, which demonstrates the superiority of catheter ablation over antiarrhythmic drug (AAD) therapy for atrial fibrillation (AF), has been hailed as a major step forward in understanding the relative efficacy and risks of these two treatment strategies. 


The Atrial Fibrillation versus Antiarrhythmic Drugs (A4) trial was an international randomized controlled multicenter study that compared catheter ablation with continued AAD therapy in patients with documented paroxysmal AF.

The study’s preliminary results were presented in May 2006 at the Heart Rhythm Society’s Annual Scientific Sessions and the full study report is published this week in the journal Circulation.

The trial enrolled 112 patients with paroxysmal AF who had previously failed at least one AAD. They were randomized to undergo catheter ablation (pulmonary vein isolation with additional extrapulmonary vein lesions where necessary) or to receive “new” AADs alone or in combination.

At 1 year, 89% of patients in the ablation group were free of AF recurrences compared with just 23% of those in the AAD group, a highly significant difference (p<0.0001). Symptom scores, exercise capacity, and quality-of-life scores were also significantly higher in the ablation group.

These differences “constitute an important benefit that may support earlier use of catheter ablation in this context,” Pierre Jaïs (Hôpital Cardiologique du Haut-Lévêque, Bordeaux-Pessac, France) and study co-authors remark.

In an accompanying editorial, David Callans (University of Pennsylvania, Philadelphia, USA) said that the A4 investigators should be congratulated for their “important contribution” to the body of research into AF treatment. He said it is now “unquestionable” that ablation is more effective than AADs, “at least in young mostly healthy patients and when performed by highly skilled practitioners.”

Important questions remain, however. These include the relative merits of ablation and AADs in patients with longstanding persistent AF and/or comorbidities; the impact of ablation on AF-associated thromboembolism and mortality; and the long-term effect of ablation on left atrial remodeling and function.

Callans concluded: “Novel ideas for increased cooperation, not to mention funding, will be required to answer questions of this magnitude, particularly because these questions develop slowly, over the course of a human lifetime.”

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