In patients with long-standing persistent atrial fibrillation (AF) despite standard treatment, additional electrical isolation of the left atrial appendage (LAA) can improve freedom from AF without increasing complications, results of the BELIEF study show.

The findings were presented in a Hot Line session at ESC Congress 2015.
"Empirical left atrial appendage isolation, along with the standard approach of pulmonary vein isolation (PVI) and ablation of extra-pulmonary triggers is superior to the standard approach alone in enhancing the long-term success rate of catheter ablation," reported investigator Luigi Di Biase, M.D., Ph.D., from Montefiore-Albert Einstein Center for Heart & Vascular Care, New York, USA and Texas Cardiac Arrhythmia Institute at St. David's Medical Center, Austin, Texas, USA.

"We first proposed in 2010 that the left atrial appendage was a relevant, under-reported trigger for AF, and now this trial confirms our findings," he added.
The study included 173 patents with "long-standing persistent" AF - defined as extending beyond one year.

Patients were randomly assigned to undergo standard treatment alone (PVI and ablation of extra-pulmonary triggers, n=88), or standard treatment plus the addition of LAA ablation (n=85).

For the primary endpoint of recurrence of AF at one year, 28% of standard treatment patients were recurrence-free compared to 56% of patients who had the additional LAA ablation (hazard ratio [HR] 1.92; p=0.001).

For patients who were not recurrence-free in either group, LAA isolation was performed in a second procedure.

At 24 months, after an average of 1.3 procedures, the cumulative success rate was 76% in the LAA ablation group and 56% in the standard treatment group. (HR 2.24; p= 0.003).

There was no difference in complication rates between groups at follow up, including transient ischemic attacks or strokes, however the mean radiofrequency time was longer in the LAA group (93 versus 77 minutes; p<0.001).

In multivariate analysis, no LAA ablation was associated with significantly higher recurrence of AF (HR 2.2; p = 0.004).

"It is logical to suggest that the LAA may initiate AF like the pulmonary veins because embryologically, the LAA grows out of the primordial LA, which is formed mainly by the adsorption of the primordial pulmonary veins and their branches," explained Dr. Di Biase.

"In fact, an earlier study conducted by our group showed that LAA firing was the source of AF in 27% of patients and, after LAA ablation, 93% of those patients were AF free at long term follow up."

The study was sponsored by Texas Cardiac Arrhythmia Research Foundation.  Dr. Di Biase is a consultant for Biosense Webster, Stereotaxis and St Jude Medical and has received speaker honoraria/travel from Medtronic, Atricure, EPiEP, Boston Scientific and Biotronik.