Low-Level Baroreceptor Stimulation Suppresses Atrial Fibrillation by Inhibiting Ganglionated Plexus Activity

Background: The autonomic nervous system (ANS) plays an important role in the initiation and maintenance of atrial fibrillation (AF), and modulation of the ANS function may contribute to AF control. Methods: Anesthetized dogs received either sham treatment (SHAM group, n = 8) or low-level carotid baroreceptor stimulation (LL-CBS) treatment (LL-CBS group, n = 8). The stimulation voltage was set at 80% below the threshold. To simulate focal AF, high-frequency stimulation (HFS) was applied to local nerves during the atrial refractory period. Multielectrode catheters were attached to the atria and all the pulmonary veins to determine the changes in the AF threshold (AF-TH), the atrial effective refractory period (AERP), and the window of vulnerability (WOV) during HFS in both groups. Microelectrodes were inserted into the anterior right ganglionated plexus (ARGP) to record neural firing. Results: HFS induced sinus rate (SR) slowing in the superior left ganglionated plexus (SLGP). LL-CBS induced a progressive increase in AF-TH and AERP at all sites and a significant decrease in the sum of WOV at 2 hours (all P < 0.05). LL-CBS inhibited the ability of SLGP stimulation to slow the SR and the mean values of frequency and amplitude of ARGP neural activity compared with the SHAM group (all P < 0.05). Conclusions: LL-CBS suppressed AF inducibility by inhibiting the neural activity of ganglionated plexuses. LL-CBS may serve as a novel therapeutic modality to treat AF.