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European Society of Cardiology

Clinical Articles, News & Views

Ablation for patients with persistent AF – best approach and benefits vs. drugs

Using catheter ablation to create complete linear lesions around pulmonary veins, proved more effective than the creation of incomplete lesions in preventing recurrence of atrial fibrillation (AF), according to results from the GAP-AF study1 presented recently in the Late Breaking Clinical Trials session I at the EHRA EUROPACE 2013 meeting held recently in Athens, Greece.

In the GAP-AF (AFNET 1) study between February 2006 and August 2010, 233 patients with drug refractory paroxysmal AF were randomised to have either a complete procedure (n=117) or an incomplete procedure (n=116). For the incomplete procedure the electrophysiologists (EPs) stopped the radiofrequency application at one site to permit reconduction from the circumference. The study, which was performed in seven German centres, was funded by the German Atrial Fibrillation Network (AFNET). The inclusion criteria for the study were that patients had to be aged over 55 years and to have been treated with one anti-arrhythmic drug before they entered the trial. Patients with poor left ventricular function were excluded from the study.

The primary endpoint of the study was the time to first recurrence of symptomatic AF with duration of more than 30 seconds on trans-telephonic electrocardiogram (ECG) monitoring, or detection of asymptomatic AF defined as two consecutive recordings of AF during a minimum of 72 hours. The study made use of a small credit card sized device that patients can place on their chest wall to record an ECG whenever they experience symptoms of AF and transmit the data via the telephone. Additionally, patients were asked to record and transmit an ECG every day regardless of their symptoms.

Results showed that at the three month follow-up, sinus rhythm (normal beating of the heart) had been achieved in 37.8% (46) of patients who had complete ablation, versus 20.8% (26) with incomplete ablation (p<0.001). Furthermore, the mean number of days in sinus rhythm was 60 days for the complete group versus 16 days for the incomplete group (p<0.001).

At three months, when patients were taken back to the EP lab for a repeat investigation, 70 % of those randomised to complete pulmonary vein isolation (PVI) had gaps versus 89% randomised to incomplete PVI.

No significant differences were found for serious adverse events (including syncope, stroke, major bleeding, tamponade) between the complete and incomplete groups.

“The study shows us for the first time that complete isolation of the pulmonary veins is more effective than incomplete isolation. It suggests that the level of evidence for complete ablation should be upgraded from class Ic to class Ia, where it is supported by a multicentre randomised trial,” said presenter Professor Karl Kuck, (Asklepios Klinik St George, Hamburg, Germany).

However, the study also highlighted that recurrence rates were high even for patients who had undergone complete isolation procedures. “Research is urgently needed to improve ablation techniques to make the complete lines more durable. There is a need to explore other energy sources and tools for catheter ablation,” Professor Kuck added.

The Study of Ablation vs AntiaRrhythmic Drugs in Persistent Atrial Fibrillation (SARA) study, also presented in the Late Breaking Clinical Trials session, found that catheter ablation therapy was superior to medical therapy for maintenance of sinus rhythm in patients with persistent AF.

Between May 2009 and November 2011 Professor Mont and colleagues, from eight ablation centres in Spain, randomly assigned a total of 146 patients with persistent AF 2:1 to catheter ablation (CA) (n=98) or antiarrhythmic drug therapy (ADT) (n=48). ADT was given according to current guidelines, with class III drugs (amiodarone) recommended for patients with structural heart disease and class Ic (flecainide) plus dilitiazem or beta blockers for patients without structural heart disease. The inclusion criteria were that patients should have experienced symptomatic persistent AF (> seven days or 50 mm anterioposterior diameters).

In an intention-to-treat analysis, the proportion of patients free of prolonged (>12 hours) AF at 12 months (the primary end-point) was 70.4% in the CA group versus 43.7% in the ADT group (p=0.002); implying an absolute risk difference of 26.6% (95% CI: 10.0-43.3) favouring ablation group.

The proportion of patients free of any recurrence of AF or flutter (lasting >30 seconds) was 60.2% in the CA group compared to 29.2% in the ADT group (p<0.001).

“Patients with persistent AF have in general been considered bad candidates for ablation, due to poor results, and the need for prolonged and aggressive procedures,” explained principal investigator Professor Lluis Mont (Atrial Fibrillation Unit, University of Barcelona, Spain).

“Our study shows that, if proper selection criteria are applied, ablation can achieve good results for patients with persistent AF,” said Professor Mont. “It’s likely to have an impact on guidelines and may contribute to an upgrade of ablation in persistent AF to category 1B.”

Further studies, he added, are now needed looking at outcomes according to ‘shape remodelling’ and levels of fibrosis. ”This should help to further stratify patients and select good candidates for ablation,” he concluded.

References

1. Late Breaking Trial Session 1. Available from http://media.ne.cision.com/l/knthwylm/bit.ly/10Algj8

Published on: July 30, 2013

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ENDORSED BY

  • ArrhythmiaAlliance
  • Stars
  • Anticoagulation Europe
  • Atrial Fibrillation Association
 

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