Neurocardiac and cerebral responses evoked by esophageal vago-afferent stimulation in humans: effect of varying intensities

doi:10.1016/S0008-6363(98)00190-4

Cardiovascular Research 1998 40(3):591-599; doi:10.1016/S0008-6363(98)00190-4
© 1998 by European Society of Cardiology

This Article

	Full Text
	FREE Full Text (PDF)
	E-letters: Submit a response
	Alert me when this article is cited
	Alert me when E-letters are posted
	Alert me if a correction is posted

Services

	Email this article to a friend
	Similar articles in this journal
	Similar articles in PubMed
	Alert me to new issues of the journal
	Add to My Personal Archive
	Download to citation manager
	Request Permissions
	Disclaimer

Google Scholar

	Articles by Kamath, M. V.
	Articles by Tougas, G.
	Search for Related Content

PubMed

	PubMed Citation
	Articles by Kamath, M. V.
	Articles by Tougas, G.

Social Bookmarking

	What's this?

Neurocardiac and cerebral responses evoked by esophageal vago-afferent stimulation in humans: effect of varying intensities

Markad V. Kamath^a, Stephan Hollerbach^b, Absar Bajwa^a, Ernest L. Fallen^a^,*, Adrian R.M. Upton^a and Gervais Tougas^a

^aDepartment of Medicine, McMaster University, 1200 Main St. West, Room 3U4, Hamilton, Ontario, Canada L8N 3Z5
^bDepartment of Internal Medicine (SH), University of Regensburg, D-93042, Regensburg, Germany

^* Corresponding author. Tel.: +1-(905)-521-2100, Ext. 6222; fax: +1-(905)-521-5053; e-mail: fallene@fhs.csu.mcmaster.ca

Objective: This study was designed to determine whether esophagealvago-afferent electrostimulation, over a wide range of stimulusintensities, can sustain a cardiac vago-efferent effect by wayof central nervous system processing. Methods: Studies wereperformed in ten healthy male subjects (23.9±6.3 years).Esophageal electrostimulation was carried out using a stimulatingelectrode placed in the distal esophagus. Stimulation of esophagealvago-afferent fibres was employed using electrical impulses(200 µs at 0.2 Hz x 128 s) varying from 2.7 to 20 mA.Respiratory frequencies, beat-to-beat heart rate autospectraand cerebral evoked potentials were recorded at baseline andat each stimulus intensity in random order. Results: With esophagealelectrical stimulation, we observed a small non-significantdecrease in heart rate. There was a dramatic shift of the instantaneousheart rate power spectra towards enhanced cardiac vagal modulationwith intensities as low as 5 mA. This effect was sustained throughoutall intensities with no further change in either the low frequencyor high frequency power. Conversely, there was a linear doseresponse relationship between cerebral evoked potential amplitudeand stimulus intensity mainly occurring above perception threshold(10 mA). Esophageal stimulation had no significant effect onheart rate or respiratory frequency at any stimulus intensity.Conclusions: These results indicate that electrical stimulationof the distal esophagus across a wide range of current intensitieselicits a reproducible shift in the heart rate power spectrumtowards enhanced vagal modulation. The data suggest a closedloop afferent/efferent circuitry wherein tonic visceral afferentimpulses appear to elicit a phasic or modulatory vago-efferentcardiac response in healthy subjects.

KEYWORDS Autonomic nervous system; Heart rate variability; Sinus node; ECG; Signal transduction; Discipline; Clinical

Add to CiteULike CiteULike Add to Connotea Connotea Add to Del.icio.us Del.icio.us What's this?

This article has been cited by other articles:

D. S. Ditor, M. V. Kamath, M. J. MacDonald, J. Bugaresti, N. McCartney, and A. L. Hicks
Effects of body weight-supported treadmill training on heart rate variability and blood pressure variability in individuals with spinal cord injury
J Appl Physiol, April 1, 2005; 98(4): 1519 - 1525.
[Abstract] [Full Text] [PDF]