Internal capacitance and resistance allow prediction of right ventricle outflow

Publisher Website
Google Scholar
Abstract
The relationship between right ventricle afterloading pressure (P) and outflow (Q) was studied in 3 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. A time-varying capacitance and series resistance adequately model internal properties of the RV that relate outflow to afterloading pressure.