Augmented destruction test with an electromechanical pulsatile total artificial heart

The total artificial heart (TAH) being developed by these authors successfully completed hydrodynamic and hemolysis studies followed by two acute implantations. Before commencing preclinical studies on any device, documentation of the reliability and durability of each component has to be done. This TAH was submitted to a 4 month destruction test under the most severe driving conditions to detect any weak mechanical components of the system. The maximum dP-dt in the left pumping chamber was chosen of more than 15,000 mm Hg/s, which is almost 6 times higher than that of the normal driving condition. The pump was submersed into a water bath that was maintained at 37 degrees C. The TAH was driven in a left master alternative (LMA) variable rate mode at 8 L/min output flow, 15 mm Hg reload, 100 mm Hg left afterload, and 25 mm Hg right afterload. The outflow, pressures, and temperature inside the TAH were monitored. Several stress concentration areas were detected. The connection between the roller nut and support plate proved to be one of the most stressed regions, and a more reliable fixing procedure was required. This portion was redesigned to offer a durable connection. No malfunctions of the actuator or controller were detected throughout the testing duration. No temperature elevation more than 1 degree C on the center piece of the TAH was demonstrated.