Abstract 12617: Low-level Tragus Stimulation: A Non-invasive Approach to Suppress Atrial Fibrillation
Background: We have recently shown that low-leveltranscutaneous electrical stimulation of the auricular branch of the vagus nerve at the tragus (LLTS), the anterior protuberance of the outer ear, suppresses atrial fibrillation (AF) in canines. We examined whether LLTS may suppress AF inducibility and duration as well as decrease acute AF-related inflammatory and prothrombotic effects in patients with paroxysmal AF.
Methods: Sixteen patients with paroxysmal AF who presented to the Electrophysiology Lab for AF ablation in sinus rhythm, were randomized to either 1 hour of LLTS (n=8) or control (n=8). LLTS (20Hz) in the right ear, 50% lower than the voltage that slowed the sinus rate, was accomplished by attaching two alligator clips onto the tragus. Burst atrial pacing was performed to induce AF at baseline and after 1 hour of LLTS or sham. Blood samples from the coronary sinus and the femoral vein were collected at baseline and after 1 hour of LLTS or sham and were analyzed for inflammatory markers, including tumor necrosis factor-α, C-reactive protein and interleukin-6, as well as the platelet activation marker P-selectin, using a multiplex immunoassay.
Results: There were no differences in relevant clinical and echocardiographic characteristics between the 2 groups. The pain threshold and threshold for slowing the sinus rate were similar. Pacing-induced AF duration significantly decreased by 11.9±5.7 min compared to baseline in the LLTS group and increased by 1.8±1.5 min in the control group (p=0.027 for comparison between groups). Likewise, pacing-induced AF cycle length increased significantly by 23.3±9.1 ms compared to baseline in the LLTS group, but decreased by 10.0±3.4 ms in the control group (p=0.026 for comparison between groups). No significant differences were seen in the atrial effective refractory period between groups. Inflammatory and platelet activation markers were low at baseline and did not change significantly with LLTS.
Conclusion: LLTS suppresses AF in patients with paroxysmal AF. Our results support the notion that autonomic neuromodulation may emerge as an alternative non-pharmacologic, non-ablative modality for the treatment of AF.
- © 2013 by American Heart Association, Inc.