AJP - Heart and Circulatory Physiology, Vol 243, Issue 2 346-H350, Copyright © 1982 by American Physiological Society
Impedance loading servo pump system for excised canine ventricle
K. Sunagawa, D. Burkhoff, K. O. Lim and K. Sagawa
To investigate ventricular-arterial system interaction, we have developed a
hybrid-computer-controlled impedance loading servo pump system that enables
us to impose a simulated arterial hydraulic impedance on an excised canine
ventricle. An analog computer programmed to simulate a three-element
Windkessel model of the arterial system computes instantaneous aortic flow
from the instantaneous ventricular pressure. The time integral of this flow
is used to command a volume servo pump system that controls the
instantaneous ventricular volume. All parameter values in the loading
system are controlled by a digital computer. The actual impedance spectrum
generated by the system was reasonably close to that expected from the
arterial model. The unique features of this system are the following. 1)
The instantaneous volume of the ventricle, which is crucial information,
can be measured. 2) If needed, the arterial impedance model can easily be
reprogrammed to generate more complex impedance spectra. 3) The vascular
parameters can be made nonlinear or time varying through the digital
computer control.
