Hemodynamic regulation in total artificial heart recipients.

The right and left atrial pressures (RAP and LAP), circulating blood volume (CBV) and pump output were analyzed in 17 calves implanted with a free-diaphragm-type total artificial heart. A high RAP and increased CBV were common features in these animals, while the LAP was maintained in a nearly normal range throughout the course. Some correlation was seen between RAP, CBV and pump output, which was maintained in the range of 86.6 to 130.1 ml/min/kg. In the atrial myocardium various morphological changes were observed accompanied by thickening of the cell, which was conspicuous after one month of implantation. To improve this high venous pressure problem, an automatic controller for pusher-plate-type pumps wtih a greater sensitivity was introduced. A preliminary in vivo study using this new system is also reported.