Abstract
We produced a new circulatory model “Piggyback Heart System” in which the artificial heart was used as a patient's heart, and the other artificial heart was connected to it as a ventricular assist device (VAD). This piggyback heart was connected to the Donov an mock circulatory system. The function of the 40ml VAD model (TMG-40-N) was tested and the methods of the driving (counterpulsation, copulsation or internal fixed pulsation) were evaluated, and we concluded that this model was valuable for this purpose. The mock left heart failure conditions were created and changed as follows. Mean arterial pressure (MAP) 43-73mmHg, total flow (TF) 1.8-2.6l/min, mean pulmonary arterial pressure 38-43mmHg, LAP 28-41mmHg, RAP 8-11cmH2O. By the VAD in counterpulse mode with a driving pressure from 180 to 210mmHg and with the rate at 100/min, a maximum flow assist of 1.9l/min and a maximum MAP increase of 35mmHg were obtained. In profound mock left heart failure, there were no significant hemodynamic differences among 3 different modes of pulsations, however in the mild mock left heart failure condition, the MAP, LAP and TF were fluctuated by driving the VAD in the internal mode, and the effect of VAD assist was unstable. The counterpulse mode seems to be the best driving method in the mild failure condition.
