AJP - Heart and Circulatory Physiology, Vol 243, Issue 1 99-112, Copyright © 1982 by American Physiological Society
Internal capacitance and resistance allow prediction of right ventricle outflow
K. B. Campbell, J. A. Ringo, Y. Wakao, P. A. Klavano and J. E. Alexander
The relationship between right ventricle afterloading pressure (P) and
outflow (Q) was studied in three isolated canine right ventricle (RV)
preparations. Right atrial pressure was held constant while graded
elevations in P were induced with stepwise occlusions of the right and left
branches of the pulmonary artery. P and Q signals were collected and
analyzed using a digital computer system. Data were analyzed by assuming a
model structure for the RV and comparing resultant model predictions of Q
with actual observations. The model structure was modified in accordance
with the discrepancy between prediction and observation to improve the
model's predictive capability. The initial model tested was the
time-varying linear relationship between ventricular volume and pressure.
Utilizing this model, accurate predictions of RV outflow in the face of
varying pressure afterloads could not be made. The addition of a series
resistance to this elementary model resulted in marked improvement in
predictive performance. The addition of greater complexity to the model
gave only marginal improvement to the model's predictive capability. It was
concluded that a time-varying capacitance and series resistance adequately
model internal properties of the RV that relate outflow to afterloading
pressure.
