The effects of LAA ligation on LAA electrical activity.

Background: The arrhythmic role of the left atrial appendage (LAA) has been implicated in the maintenance of persistent atrial fibrillation. LAA isolation with catheter ablation has been successful but is limited by the risk of tamponade and electromechanical dissociation with the potential for LAA thrombus formation.
Objective: To assess whether LAA ligation results in LAA electrical isolation.
Methods: A total of 68 patients with contraindication or intolerance to oral anticoagulation therapy underwent LAA ligation with the LARIAT suture delivery device. Patients had unipolar [n = 30(44%)] or bipolar [n = 38(56%)] voltage measurements pre- and post-LAA ligation.
Results: All 68 patients underwent successful LAA ligation. There was a statistically significant reduction in the mean LAA voltage from pre-ligation (unipolar pre-ligation voltage 1.1 ± 0.53 mV; bipolar pre-ligation voltage 4.7 ± 2.83 mV) to post-ligation (unipolar post-ligation voltage 0.3 ± 0.38 mV; bipolar post-ligation voltage 0.6 ± 0.27 mV). Ninety-four percent of the patients had a reduction in the LAA voltage after the closure of the snare, with 10 of 30 (33%) of the patients having complete elimination of LAA voltage with the initial tightening of the suture. Pacing from the LAA after the closure of the snare resulted in lack of capture of the left atrium in 28 of 31 patients.
Conclusions: The snare closure of the LAA using the LARIAT device produces an acute reduction in the LAA voltage and inhibits the capture of the left atrium during LAA pacing. Future studies are needed to determine whether LAA ligation affects atrial fibrillation burden.
(Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)