A DYNAMIC-MODEL OF VENTRICULAR INTERACTION AND PERICARDIAL INFLUENCE

A mathematical model describing the dynamic interaction between the le ft and the right ventricle over the complete cardiac cycle is presente d. The pericardium-bound left and right ventricles are represented as two coupled chambers consisting of the left and right free walls and t he interventricular septum. Time-varying pressure-volume relationships characterize the component compliances, and the interaction of these components produces the globally observed ventricular pump properties (total chamber pressure and volume). The model 1) permits the simulati on of passive (diastolic) and active (systolic) ventricular interactio n, 2) provides temporal profiles of hemodynamic variables (e.g., ventr icular pressures, volumes, and flow) that agree well with reported obs ervations, and 3) can be used to examine the effect of the pericardium on ventricular interaction and ventricular mechanics. It can be reduc ed to equivalency with models previously reported by invoking simplify ing assumptions. Furthermore, model-generated ''dynamic interaction ga ins'' are employed to quantify the mode and degree of ventricular inte raction. The model also yields qualitative predictions of septal and f ree wall displacements similar to those detected experimentally via M- mode echocardiography. Such analogies may be ext ended easily to the s tudy of pathophysiological states via appropriate modifications to 1) the pressure-volume characteristics of the component walls (and/or per icardium) and/or 2) the specific time course of activation of the vent ricular free wall or the septum. A limited number of examples are incl uded to demonstrate the utility of the model, which may be used as an adjunct to new experimental investigations into ventricular interactio n.