New technique for vagal nerve stimulation.
BACKGROUND
The vagus nerve travels in a neurovascular bundle with the carotid artery and internal jugular vein. The present study was designed to assess whether transvascular stimulation through the carotid artery of the dog can be used to directly stimulate the vagus nerve and increase parasympathetic tone.


METHODS
In five anesthetized dogs, a steerable electrode catheter was positioned under fluoroscopic guidance in the right carotid artery in the mid neck via the femoral artery. Multipolar catheters were positioned transvenously through the femoral vein in the right atrium, across the tricuspid valve to record a His-bundle electrogram, and in the right ventricle.


RESULTS
In all five animals, vagal nerve stimulation was successfully achieved with outputs ranging between 10 and 30 mA. Sinus cycle length increased from 473 +/- 113 ms at baseline to 894 +/- 315 ms (P < 0.025) during stimulation from the right carotid artery. There was an increase in the AH interval from 55 +/- 14 to 77 +/- 23 ms (P < 0.03), a shortening of the atrial effective refractory period from 136 +/- 8 to 126 +/- 6 ms (P < 0.01), and a fall in the systolic blood pressure from 135 +/- 20 to 117 +/- 20 mmHg (P < 0.005) with stimulation from the right carotid artery. A prolongation of the AV and VA block cycle lengths and the AV nodal effective refractory period was also noted with stimulation from the right carotid artery. Atrial fibrillation was not induced at baseline in any animal. During stimulation from the right carotid artery, atrial fibrillation was induced in three of five animals and persisted for the duration of stimulation from the right carotid artery.


CONCLUSIONS
Cardiac parasympathetic stimulation can be achieved by positioning a catheter in the neurovascular bundle in the neck adjacent to the vagus nerve with resultant effects on cardiac electrophysiology.
Goldberger
J J
JJ
Department of Medicine and the Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA. j-goldberger@nwu.edu
Kadish
A H
AH
Johnson
D
D
Qi
X
X
D000818:Animals; D001283:Atrioventricular Node / Q000502:physiology; D002339:Carotid Arteries / Q000601:surgery*; D004285:Dogs; D004558:Electric Stimulation / Q000379:methods*; D004562:Electrocardiography; D013997:Time Factors; D014630:Vagus Nerve / Q000502:physiology*