A compact and noise free electrohydraulic total artificial heart.

The ABIOMED total artificial heart (TAH) is designed for long-term tether-free use in patients with end-stage heart disease. Blood pumping is achieved through hydraulic fluid motion across flexing diaphragms. The hydraulic power is derived from a miniature centrifugal pump (50% efficiency). Flow directional change needed for alternate left and right filling and ejection is achieved with a rotary valve. With no mechanical contact with the flexing membrane, the wedge angle between the two pumps sandwiching the energy convertor can be easily optimized for anatomic fit. The blood pumps (80 ml strokes) are fitted with trileaflet polyetherurethane valves (24 mm). The TAH is implanted using twist-lock stepless quick connectors to the inflow cuffs and outflow grafts. Left-right flow balance is achieved with an atrial hydraulic shunt placed between the left cuff and inflow valve. Animal studies show that the TAH fits very well in Long Horn calves weighing 90 to 100 kg and can provide cardiac output in excess of 10 L/min. A cadaver (85 kg) study showed the TAH fits within the pericardial region.