The Baylor Electromechanical Total Artificial Heart

A totally implantable electromechanical total artificial heart (TAH) system has been developed in our institute. This pump is very small (outer diameter, 97 mm; central thickness, 83 mm; and weight, 620 g), demonstrating a good anatomical fit in the pericardial space of 26 heart transplant recipients. The actuation mechanism is simple, and all the components are commercially available with proven longterm durability, thus allowing easier fabrication. The pump can be easily and simply controlled by reliable Hall effect sensors with left master alternate (LMA) mode. Four newly fabricated TAHs demonstrated quite similar pump performances. This TAH has a reproducible high performance with good quality assurance. In vitro performance mapping demonstrated that the pump can provide a maximum flow of 91/ min, with a high sensitivity to preload and a low sensitivity to afterload. During 4 months of accelerated endurance testing in 42°C saline, no electromechanical troubles were observed and power requirement remained constant, indicating a stable and reliable performance. After modification of the inflow valve angle, excellent flow paterns inside the blood chamber were demonstrated in this study, in which laser light and a high-speed camera were used. In vivo feasibility tests were performed successfully in eight calves for up to 1 week, demonstrating the readiness to move forward to longterm in vivo studies. This small, simple, reliable, and durable mechanically driven totally implantable TAH system is suitable for a permanent heart replacement.