AJP - Regulatory, Integrative and Comparative Physiology, Vol 246, Issue 2 267-R270, Copyright © 1984 by American Physiological Society
Exaggerated wave reflection in the kangaroo simulates arterial counterpulsation
A. P. Avolio, W. W. Nichols and M. F. O'Rourke
The ascending aortic pressure wave in kangaroos is quite different from
that seen in other experimental animals and in humans, despite an ascending
aortic flow wave that is virtually identical. The diastolic pressure surge
in the ascending aortic pressure wave of kangaroos is very prominent--so
much so that peak diastolic pressure is often greater than peak systolic
pressure, with the pressure wave resembling that recorded in humans during
intra-aortic balloon counterpulsation. Ascending aortic impedance patterns
in kangaroos indicate the presence of a single functionally discrete
reflecting site in the peripheral circulation, with high reflection
coefficient. All findings--of pulse contour and impedance patterns--are
explicable on the basis of arterial anatomy and body shape. Wave reflection
from the distant, large, and vascular lower body appears to dominate the
effects of wave reflection from the short, small, and less vascular head
and forelimb system.
