Theoretical and experimental analysis of right ventricular bypass and univentricular circulatory support

The dynamic coupling between cardiac pump events and vascular arterial-venous factors that regulate the rate of blood flow around the circulation is examined. A series of experiments was designed to test the feasibility of maintaining vascular and pulmonary function in the absence of the right heart and to characterize the physiologic and hemodynamic consequence of such an exclusion. Theoretical analysis of the cardiovascular system (excluding neuro-humoral factors), using both lumped time invariant and distributed compartmental mathematical equivalent representations, demonstrated that a change in cardiac output has an inverse-linear effect on venous and direct-linear effect on arterial pressure. A single blood pump, in a form of a mechanical substitute for the biologic left heart, alone can support the circulation. Cardiac output reserve is limited (50% of normal) because of the rapidly diminishing pulmonary venous pressure as outflow is increased, irrespective of the pump´s specific characteristics.