This report summarizes the results of the in vitro evaluation of Soviet and American artificial hearts. The devices were tested at the All-Union Institute of Transplantation and Artificial Organs, Moscow, U.S.S.R., and Baylor College of Medicine, Houston, Texas, U.S.A. These studies were designed to standardize procedures to allow comparison of artificial ventricles of different designs. Also, these studies might provide a means for evaluation of other characteristics such as hemolysis, durability, and reliability. Static and dynamic tests were performed, varying preload, afterload, rate, and systolic and diastolic time intervals. All designs demonstrated comparable function curves with capability of taking over the pressure and volume work of the natural heart.

Automatic control systems for the artificial heart (AH) and ventricular assist device were developed using selected criteria of effectiveness, a mathematical model of regulation, and noninvasive measures of the hemodynamic parameters. The Sinus IS2 system was developed for control of the AH; its main component is a high-speed servomechanism that provides for the generation of pneumatic pulses. The servomechanism is controlled by automatic regulation with pressure feedback. Mean aortic pressure was used as the primary regulated hemodynamic parameter. The systems were tested using both a physical model and a physiologic experiment. Contractile insufficiency of the left ventricle was simulated in testing the control system for circulatory assistance. The studies demonstrate that automatic control systems function effectively by providing normal blood circulation in both the resting state and in certain transient processes occurring in a real, dynamic circulatory system.

Using a new heart-lung machine developed at our Institute, experiments were conducted on dogs, donkeys, and monkeys, providing complete and assisted artificial circulation, assisted oxygenation, and perfusion preservation of the heart. The new apparatus consists of two sequentially mounted artificial ventricles working in an antiphase mode; blood oxygenation is accomplished by a reusable oxygenator with a fluorocarbon preoxygenator. Experimental results indicate that clinical use of the apparatus is promising and deserves consideration. The conditions of perfusion were close to physiological conditions and provided long-term survival of the animals. Performance in left ventricular bypass was optimized by monitoring myocardial PO2 and the state of the quick-connect/cut-off assemblies.

No abstract

No abstract