EDMONTON, Alberta -- October 30, 2009 -- Complex fractionated electrograms (CFE) combined with pulmonary vein isolation (PVI) was by far the best approach tested for freeing patients from atrial fibrillation (AF), according to research presented at the 2009 Canadian Cardiovascular Congress (CCC).
The international, randomised Substrate Versus Trigger Ablation for Reduction of Atrial Fibrillation (STAR-AF) study demonstrated that PVI was more effective than CFE, but that the combination of PVI and CFE was superior to either method alone in a test of the 3 strategies for freedom from AF at 12 months.
"The success rate with CFE alone was less than 40% in a population with a relatively high AF burden," reported Atul Verma, MD, Southlake Regional Health Center, Newmarket, Ontario, speaking here on October 28. The success rate with the combination of CFE and PVI was nearly 90% among those who received the 2 procedures.
In this study, conducted at 4 centres in Canada and 4 centres in Europe, 100 drug-refractory patients with paroxysmal AF -- defined as at least 4 episodes lasting more than 6 hours in the previous 6 months -- were randomised in single-blind fashion to CFE alone (n = 34), PVI alone (n = 32), or CFE plus PVI (n = 34).
For CFE, automated software was employed to identify and ablate all sites of significant electrical activity until the AF was terminated. For PVI, all 4 pulmonary vein antra were isolated, AF was inducted for mapping, and ablation was performed until noninducibility. As part of the protocol, second procedures were allowed, but the initially assigned procedure had to be repeated.
Repeat procedures were required in only 15% of those randomised to CFE plus PVI, which was a significantly lower amount than the 47% of CFE patients (P = .04) who received a repeat procedure or the 31% in the PVI-alone group. After either 1 or 2 procedures, 88% of subjects remained free of AF at the end of 12 months, which was significantly greater than those receiving CFE alone (38%) or PVI alone (68%) (P = .01).
Nearly all subjects in all groups were off antiarrhythmics at the end of the study.
The subjects in this trial had a high AF burden (with a mean of 16 paroxysmal episodes/month each lasting 15 hours). Dr. Verma indicated that the difference in the results favouring CFE plus PVI over either technique alone in this trial is, therefore, especially convincing. This trial is one of the first randomised trials to compare treatment strategies in this patient population, Dr. Verma noted.
The CCC is co-hosted by the Canadian Cardiovascular Society and the Heart and Stroke Foundation of Canada.
[Presentation title: Substrate vs Trigger Ablation for Reduction of Atrial Fibrillation (STAR-AF): An International, Multicenter, Randomized Trial. Abstract 923]
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