Analysis of hemodynamic response with 1/R control on biventricular bypass goat

A conductance and arterial pressure based method (1/R control) to determine the cardiac output (CO) of a total artificial heart (TAH) was developed to provide a central nervous system with control over the output of TAH. In order to clarify the deference in hemodynamic response between natural heart and 1/R control, biventricular bypass was introduced in the goat. After 2 pneumatically driven sac-type blood pumps were connected to the natural heart, the pulmonary artery was totally clamped to acquire 100% right heart bypass, and the ascending aorta was stenosed to acquire about 60 to 90% left heart bypass; 1/R control was performed substituting the output of the right artificial heart for the CO. The results demonstrated that stable control could be achieved. A discrepancy was often seen between the pulse rate (PR) of the artificial heart and the heart rate (HR) in absolute value. However, the relative changes of PR were quite similar to that of HR for the most part, indicating that the responses of 1/R control were the duplication of natural cardiac responses in normal daily activity.