Flow balance between the left and right cardiac output of an eccentric roller type total artificial heart

We have made an eccentric roller type total artificial heart (ERTAH). The E RTAH is a positive-displacement device comparable to a DeBakey roller pump. Its left and right outputs are determined by the size of its blood chamber s, and the ratio of its left and right output is almost constant. We focuse d on an interatrial shunt to achieve left-right balance. We have conducted numerical simulation, a mock test, and an acute animal experiment to analyz e left-right heart balance during ERTAH operation. Numerical simulation was performed under conditions in which the flow of the left artificial heart was fixed at 6 L/min, the flow of the right artificial heart was varied fro m 4.8 to 6 L/min, and the interatrial resistance was also varied. The relat ionship between the interatrial shunt flow rate and the output of the left and right artificial hearts was balanced when the flow of the right artific ial heart was at 5.45 L/min. In a mock test, 2 DeBakey roller pumps were co nnected to the left and right sides of a Donovan mock circulatory system, a nd an inter-atrial shunt was created between the inlet ports of the left an d right roller pumps. The interatrial resistance of the mock system was var ied from 7.7, to 4.3, and to 2.9 mm Hg.min/L when the inner diameter of the interatrial shunt was 6, 8, and 10 mm, respectively. As in the mock test, 2 roller pumps were used to bypass the right and left hearts of a goat weig hing 60 kg. The flow rate of the left. heart was almost constant (4.7 L/min ). The now of the right heart was approximately 4.1 L/min when the interatr ial shunt now rate was zero. A leading consideration was that the left to l eft shunt through the bronchial arteries in this goat was approximately 0.6 L/min. In developing the ERTAH, we considered that creating an interatrial shunt between the inlet ports of the ERTAH as well as making a difference between the chamber volumes might be effective in balancing the left-right sides of the artificial heart.