A simple and compact total artificial heart for temporary use

Thromboembolism and anatomic fit are the major issues to be addressed in the design of a heart replacement device for total circulatory support. In an attempt to overcome these problems, a simple 70 mm3 displacement pusher plate, low pressure, pneumatically driven TAH was developed for temporary use. For optimal anatomic fit, easy implantation, and better flow patterns, the 5.7 X 10.7 cm total artificial heart (1) TAH was made of two essentially flat pumps integrated into a single unit. This single package approach avoids the dead space that occurs between the two pieces of conventional TAH and thus minimizes overall volume. It was designed to be positioned in the pericardial sac in a fashion similar to the natural ventricles and, based upon previous anatomic studies, fit in the average sized adult patient. In contrast to conventional free diaphragm pumps, the diaphragms of this TAH are supported by pusher plates that have a unique guide mechanism at the center to ensure a linear-controlled diaphragm motion and consequent uniform blood flow distribution. The guide of each pusher plate nests into the other, resulting in minimal thickness of the package. By using a simple displacement transducer, reliable output monitoring, with the possibility of selection of various pumping modes and adjustment of stroke volume, is possible. The authors anticipate this efficient and practical TAH to be a suitable temporary heart replacement device.