AJP - Heart and Circulatory Physiology, Vol 270, Issue 4 1381-H1383, Copyright © 1996 by American Physiological Society
Vagal withdrawal as a function of audience
R. De Meersman, S. Reisman, M. Daum and R. Zorowitz
Department of Rehabilitation Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
This investigation examined the effects of psychosocial influences upon
vagal cardiac activity. In this crossover, counter-balanced study, 15
subjects were assessed for vagal cardiac activity before and during a
presentation in the presence and/or absence of an audience.
Electrocardiograms (ECG) were collected throughout the epochs of interest,
using a portable holter monitor system. Power spectral density analyses
were used to decompose autonomic rhythmicities of heart rate variability.
Significantly diminished vagal power was noted before and during
presentation episodes with an audience compared with vagal power during a
presentation without an audience (P < 0.05). Because respiration
modulates autonomic outflow, ECG-derived respiration was derived and
compared for all epochs, and no significant differences were noted. The
real-life findings in the current investigation are strongly suggestive of
the modulating effects of psychosocial interactions upon vagal cardiac
electrophysiology and should be considered when assessing autonomic status.
