Different stroke volumes for the left and right ventricles in the moving-actuator type total artificial heart.

A new electromechanical moving-actuator type total artificial heart (TAH) has been developed to solve the imbalance problem without an extra compliance chamber. A different stroke volume was achieved by the large left sac size and the asymmetry of the actuator motion referred to the center position. The left ventricle consists of a double sac with the outer sac attached to the actuator providing active diastolic filling, while the double sac of the right ventricle being free from the actuator, and having sufficient suction produced due to the rigid pump housing. The stroke volume difference between the left and right sac is compensated through the air in the interventricular space of the variable volume (VV) space. Computer simulation based on the geometrical relationships between the blood sacs and the actuator was performed to simulate the physical mechanisms of the moving-actuator type TAH. Results were then compared with the measured pressure changes in various chambers of the pump and the stroke volume differences in mock circulation test. In two acute calf experiments, the balanced left and right atrial pressures were achieved in the moving-actuator type TAH without an extra compliance chamber.