Complex fractionated atrial electrograms (CFAE) ablations and continuous electrical activity (CEA) ablations have been proposed or the treatment of persistent atrial fibrillation (AFib). But a new study suggests targeting bipolar electrograms with less fractionation. According to the researchers, these may be better targets because they are more likely to be focal electrical sources.

The study—led by Simon Kochhäuser, with the Southlake Regional Health Centre, Newmarket, Ontario, Canada—was published online August 2 in the Journal of the American College of Cardiology.

The team developed a new algorithm to identify focal electrical sources, based on their assumption that focal electrical sources would exhibit regular electrical activity with centrifugal wave propagation.

“Using this algorithm, our objective was to evaluate the spatial relationship of focal electrical sources to CFAE and CEA in AFib patients,” they wrote.

The authors describe their study as the first one to explore the spatial relationships of fractionated EGMs to focal electrical sources in the left atrium of patients with persistent AFib or a high burden of paroxysmal AFib.

The study cohort comprised 66 patients who had complete follow-up in the SELECT-AF (Selective complex fractionated atrial electrograms targeting for atrial fibrillation) trial. Among that group of 66, 34 (52 percent) underwent CEA ablation. The other 32 patients (49 percent) had CFAE ablation with the endpoint of complete elimination of local bipolar electrograms.

At one-year follow up, 42 of the group (64 percent) had AFib recurrence. The other 24 patients (36 percent) remained free of AFib. There were no baseline differences between these two groups. 

Their analysis revealed that the number of unablated focal electrical sources and the CEA ablation approach significantly predicted AF recurrence.

They discovered that focal electrical sources frequently localize outside CFAE and CEA areas. They maintained that this suggests that mores CFAE and CEA areas may be passive to AF maintenance. “Instead of eliminating CFAE and CEAs completely, bipolar EGMs with less fractionation may represent more suitable targets, as they are likely to be focal electrical sources,” they concluded.