An electrohydraulic total artificial heart with a separately placed actuator

An electrohydraulic total artificial heart (EHTAH) system, consisting of a separately placed actuator and blood pumps with good anatomic fit, was designed. In the actuator is a brushless DC motor sandwiched between two metal bellows or two pusher-plate pumps connected with the blood pumps by polyvinylchloride tubes. A roller-screw system coupled with the bellows is used for alternative pumping, and silicone oil transmits the action. The pumps are elliptical, and the right pump has a flatter and longer shape than the left to fit the extremely short distance between the right atrium and the sternum. To evaluate in vivo performance, the pumps were implanted as a pneumatic system in a calf weighing 53 kg and three goats weighing 54-55 kg. The pump fit well in the animals, and the calf survived for 111 days, and one goat was alive for 8 days. The EHTAH system could provide an output of 6 L/min with pusher-plate pumps as oil chambers on in vitro evaluation. This system could become one of the most suitable approaches for a totally implantable system.