CONSTRUCTIONAL AND FUNCTIONAL-CHARACTERISTICS OF RECENT TOTAL ARTIFICIAL-HEART MODELS TNS BRNO VII, VIII, AND IX

Twelve total artificial heart (TAH) models have been developed at the Bmo Research Center. Devices VII, VIII, and IX were constructed on the principle of asymmetry. Three main objectives had to be fulfilled by this construction. First, contact of the flap inflow valve with the di aphragm during the pumping cycle had to be avoided. Second, the evacua tion regimen of the blood chamber needed to be improved. Third, the da nger of thrombi formation due to the lesser incidence of the dead corn ers had to be decreased or eliminated. The type VII heart has a roof-s haped polyurethane valve in the outflow tract whereas the type VIII he art has a flap valve. The decrease of thrombi incidence around the out flow valve was thus secured, and the driving pressure was decreased as well. In the type IX heart, the small additional flap valve is attach ed to the outflow valve. In one Brno VII device, Imachi's jellyfish va lve has been mounted. Altogether, 62 long-term experiments with surviv al times of 30-314 days have been performed. To this number, 4 compara tive experiments using the Restock artificial heart were added.