Empirical electrical isolation of the left atrial appendage (LAA) for the treatment of long-standing persistent (LSP) atrial fibrillation (AF) improved freedom from AF and atrial tachycardia (AT) without increasing complications compared with standard ablation. Luigi Di Biase, MD, PhD, Albert Einstein College of Medicine, Bronx, New York, USA, presented data from the BELIEF study [NCT01362738].

LSP AF is difficult to treat with catheter ablation [Tilz RR et al. J Am Coll Cardiol. 2012]. This is likely due to multiple origins of AF, including from the pulmonary vein and regions such as the superior vena cava, ligament of Marshall, coronary sinus, crista terminalis, left atrial posterior wall, and LAA [Di Biase L et al. Circulation. 2010]. The purpose of this study was to determine if the empirical electrical isolation of the LAA, in addition to pulmonary vein isolation and ablation of extrapulmonary triggers, would improve freedom from AF or AT.

The BELIEF trial was a randomized, open-label, parallel-group trial with 173 patients who had LSP AF that was refractory to antiarrhythmic drugs. Patients were randomized to undergo empirical electrical isolation of the LAA plus standard ablation or standard ablation alone. The primary end point was recurrence of AF/AT lasting > 30 seconds. The secondary end points were postablation heart failure or AF-related hospitalization, stroke, and mortality.

At baseline, the mean age was 64 years, 68% of patients had hypertension, and 20% had diabetes. The CHADS₂ score was 0 in 23.1% of patients, 1 in 35.3% of patients, and ≥ 2 in 41.7% of patients. The mean radiofrequency time was 93.1 and 77.4 minutes (P < .001) for the LAA and standard-of-care (SOC) arms, respectively. In the LAA arm, the LAA could not be isolated in 11 patients due to technical difficulty, and ablation was performed with only partial isolation. In the SOC arm, 9% of patients demonstrated sustained arrhythmia from the LAA and these patients were treated with LAA isolation.

Patients who underwent LAA isolation experienced a significantly greater single-procedure success rate (56%) compared with patients who underwent standard ablation (28%; HR, 1.92; 95% CI, 1.3 to 2.9; log-rank P = .001) at 12 months. The cumulative overall success was 76% in the LAA arm compared with 56% in the SOC arm (HR, 2.24; 95% CI, 1.3 to 3.8; log-rank P = .003).

At 6 months, all patients who received LAA isolation underwent transesophageal echocardiography (TEE). In 48 patients, low peak flow velocity defined as < 0.4 m/s was detected, as well as 1 patient with a LAA thrombus and 1 patient with LAA smoke. Function was preserved in 48% of patients. There were no differences in AF and heart failure–related hospitalization in the LAA isolation arm compared with the SOC arm. There were no treatment-related deaths, and 4.5% of patients in the SOC arm experienced a stroke. There were no strokes or transient ischemic attacks in the LAA arm. Periprocedural complications included pericardial effusion (1 patient in each arm) and gastrointestinal bleeding (1 in the SOC arm).

Dr Di Biase concluded that the results of the BELIEF trial suggest that empirical electrical isolation of the LAA in patients with LSP AF improved freedom from AF/AT without increasing complications associated with treatment.