BELIEF: Isolating Left Atrial Appendage May Halt Persistent AF

Marlene Busko

August 31, 2015

LONDON, UK — In patients with persistent, recurrent atrial fibrillation (AF), performing electrical isolation of the left atrial appendage (LAA) as well standard catheter ablation and pulmonary-vein isolation may increase the chance of success, according to results from the BELIEF trial[1]. However, two experts caution that it is too soon to recommend LAA isolation for all patients with persistent, recurrent AF.

Dr Luigi Di Biase (Montefiore-Albert Einstein Center for Heart & Vascular Care, New York, and Texas Cardiac Arrhythmia Institute at St David's Medical Center, Austin), presented the BELIEF trial findings here in a hot-line session at the European Society of Cardiology 2015 Congress.

Dr Luigi Di Biase

"The results of this randomized study show that after a single and redo procedure in patients with long-standing persistent AF, the empirical isolation of the LAA improved long-term freedom from atrial arrhythmias without increasing complications," Di Biase said in a press briefing.

Standard catheter ablation is challenging and often unsuccessful in halting AF in patients who have had AF for a year or longer that does not respond to antiarrhythmic drugs, Di Biase told heartwire from Medscape. "We are proposing a way to improve this," he said. "We do believe [LAA isolation] should be the standard of care in patients with longstanding AF," he later told the hot-line-session audience.

However, although the assigned discussant, Dr Gerhard Hindricks (University of Leipzig, Germany), agreed that BELIEF provides "interesting, important" insights, it is only hypothesis generating, he stressed. "Should LAA isolation be recommended as an integral part of catheter ablation of longstanding, persistent atrial fibrillation?" he asked. "No. Further studies are necessary before such a recommendation."

Similarly, comoderator Dr Elliot M Antman (Brigham & Women's Hospital, Boston, MA) told heartwire that "the bottom line is I'm not sure that [76%] was a high-enough success rate, and [that 2 years was] a long-enough follow-up to be confident that we can safely discontinue oral anticoagulation."

A BELIEF in LAA Isolation, Not Shared by All

Several studies have shown that areas other than the pulmonary vein— such as the coronary sinus, the left atrial posterior wall, and the LAA—may be the site that triggers AF, said Di Biase. In 2010, they published a study showing that the LAA is an underrecognized trigger site of AF[2], and other researchers reported similar results.

BELIEF was a multicenter trial that randomized 173 patients with persistent AF: 85 patients received standard ablation plus LAA isolation (group 1) and 88 patients received standard ablation alone (group 2).

Patients in both groups had a mean age of 64, and about 85% were male. The procedure took a mean of 16 minutes longer for patients who underwent standard ablation plus LAA isolation vs standard ablation alone (93 minutes vs 77 minutes, respectively).

Compared with patients who had only the standard procedure, those who also had LAA isolation were almost twice as likely to be free of AF at 1 year: 56% vs 28% (hazard ratio 1.92; P=0.001).

Among patients who continued to have atrial fibrillation, 62 patients (27 in group 1 and 35 in group 2) had a repeat ablation that included LAA isolation.

At 2 years, 76% of patients who had received standard ablation plus LAA isolation at baseline vs 56% of patients who had received only the standard procedure at baseline were free of arrhythmia (hazard ratio 2.24; P=0.003)

Transesophageal echocardiogram tests from 93 patients who had undergone LAA isolation (85 in group 1 and eight in group 2) showed that 48% had preserved ejection fraction, but 52% had impaired function, including slow LAA peak-flow velocity.

Four patients (4.5%) in the standard-ablation group had a stroke. No patients died. One patient in each group had pericardial effusion, and one patient in the standard-ablation group had gastrointestinal bleeding.

The study showed that pulmonary-vein triggers of AF are important in paroxysmal AF, but in longstanding persistent AF they are less important and LAA is more important, Di Biase noted. However, further studies are needed to determine the physiopathology behind these findings, he said.

Hindricks suggested that the study would have been stronger if the LAA intervention had not been performed in the control group. Also, he wondered why the stroke rate was so high in patients who did not undergo LAA isolation. Di Biase replied that the strokes occurred in patients who were not compliant with taking anticoagulants.

Session comoderator Antman wanted to know: "Are you prepared to stop the anticoagulant? How would you decide?"

Di Biase replied that according to European and US guidelines, anticoagulants should not be discontinued for patients who have a CHADS2 score of >2—which was the case for about 50% of the patients in this cohort. These patients, whether or not they had LAA isolation, should be on oral anticoagulants.

"These are patients that do not come to the [electrophysiology] table because they had to discontinue anticoagulant, they came to the [electrophysiology] table because they benefit from sinus rhythm," he said.

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

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