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Effects of Chronic Left Vagal Stimulation on Visceral Vagal Function in Man
Author(s) -
TOUGAS GERVAIS,
FTTZPATRICK DEBBIE,
HUDOBA PETER,
TALALLA ANDREW,
SHINE GLENN,
HUNT RICHARD H.,
UPTON ADRIAN R.M.
Publication year - 1992
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1992.tb02938.x
Subject(s) - medicine , vagus nerve , stimulation , vagal tone , cardiology , autonomic nervous system , heart rate , blood pressure
We examined the effects of chronic left vagal electrostimulation on afferent and efferent gastrointestinal vagal function in eight patients. Afferent function was assessed using cortical evoked responses to electrical stimulation of the esophagus and to direct vagal stimulation using the implanted left vagal electrode. Efferent gastrointestinal vagal function was measured by examining the basal, maximal, and sham fed stimuJated gastric acid output prior to and with chronic left vagal electrostimulation. Esophageal electro‐stimulation produced a cortical evoked response consisting of three negative and three positive peaks within 400 msec after stimulation. Prior to vagal eJectrostimulation the mean conduction velocity of the afferent signal was measured at 8.72 ± 3.39 m/sec, compatible with A‐delta fibers involvement. Basal, maximal, and sham fed acid output were 1.11, 21.87, and 9.37 mmol/hour, respectively. The evoked response to esophageal electrical stimulation was not changed with chronic left vagal electrostimulation. Direct vagal stimulation also produced evoked potentials that were comparable to those obtained with esophageal stimulation. The mean conduction velocity was 6.26 ± 2.72 m/sec (NS) so that there was no evidence of loss of myelinated fibers with chronic stimulation. No differences were detected in basal (1.29 mmol/h), maximal (21.64 mmol/h), or sham fed stimulated (8.03 mmol/h) acid output, showing that vagal electrostimulafion has no effect on either total or vagally mediated acid output, an efferent vagal function. In conclusion, chronic left vagal electrostimulation has no significant adverse effect on gastrointestinal vagal function.