title: Low-level right vagal stimulation: anticholinergic and antiadrenergic effects.
abstract: BACKGROUND
  We sought to extend the use of low-level vagal stimulation by applying it only to the right vagus nerve (LL-RVS) to suppress atrial fibrillation (AF).
  
  
  METHODS
  In 10 pentobarbital anesthetized dogs, LL-RVS (20 Hz, 0.1 ms pulse width) was delivered to the right vagal trunk via wire electrodes at voltages 50% below that which slowed the sinus rate (SR) or atrio-ventricular conduction. Electrode catheters were sutured at multiple atrial and pulmonary vein (PV) sites to record electrograms. LL-RVS continued for 3 hours. At the end of each hour, 40 ms of high-frequency stimulation (HFS; 100 Hz, 0.01 ms pulse width) was delivered 2 ms after atrial pacing (during the refractory period) to determine the AF threshold (AF-TH) at each site. Other electrodes were attached to the superior left ganglionated plexi (SLGP) and right stellate ganglion (RSG) so that HFS (20 Hz, 0.1 ms pulse width) to these sites induced SR slowing and acceleration, respectively. Microelectrodes inserted into the anterior right ganglionated plexi (ARGP) recorded neural activity.
  
  
  RESULTS
  (1) Three hours of LL-RVS induced a progressive increase in AF-TH at all sites (all P < 0.05). (2) The SR slowing and acceleration response induced by SLGP and RSG stimulation, respectively, was blunted by LL-RVS. (3) The frequency and amplitude of the neural activity recorded from the ARGP were markedly inhibited by LL-RVS.
  
  
  CONCLUSIONS
  LL-RVS suppressed AF inducibility and the chronotropic responses to parasympathetic and sympathetic stimulation. Inhibition of neural activity in the GP may be a mechanism underlying these results.
authors.affiliation: Heart Intervention Center, Affiliated Hospital of Ningxia Medical College, Ningxia, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Sha
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Scherlag
authors.forename: Lilei
authors.initials: L
authors.lastname: Yu
authors.forename: Xia
authors.initials: X
authors.lastname: Sheng
authors.forename: Warren M
authors.initials: WM
authors.lastname: Jackman
authors.forename: Ralph
authors.initials: R
authors.lastname: Lazzara
authors.forename: Sunny S
authors.initials: SS
authors.lastname: Po
mesh_terms: D000320:Adrenergic Fibers; D000818:Animals; D001281:Atrial Fibrillation / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial; D002799:Cholinergic Fibers; D004195:Disease Models, Animal; D004285:Dogs; D004558:Electric Stimulation; D022062:Electrophysiologic Techniques, Cardiac; D005725:Ganglia, Autonomic / Q000503:physiopathology*; D006325:Heart Atria / Q000294:innervation; D011667:Pulmonary Veins / Q000294:innervation; D013997:Time Factors; D055536:Vagus Nerve Stimulation