Consequences of the Diaphragm Driven Artificial Heart–Animal Implantation and Mock Circulation Studies

Abstract

The effects of air-driven diaphragm, artificial hearts implanted with either cardiopulmonary bypass or deep hypothermia were studied in ten calves surviving beyond the initial effects of surgery (beyond 40 hours). Calves were maintained up to ten days with normal aortic blood pressures, but with elevated right ventricular and pulmonary artery pressures and gradually inceasing venous pressure, and symptoms of right artificial heart failure. Smooth, Silicone rubber-surfaced, artificial hearts produced less blood damage than rough-surfaced hearts of Dacron fibrils; however, there was greater evidence of embolization with the smooth hearts. Mock circulation studies indicate that an asynchronously beating atrium as occurs in the calf experiments can drastically reduce cardiac output Elimination of the high C-wave which occurs with the artificial heart could be demonstrated on the mock circulation with the use of an active valve. The major problem with the present artificial heart is postulated to be at the inflow. Asynchronously beating atria with high pressure pulses and compression of the artificial heart against the natural atria and inflow vessels severely decreases cardiac output The effects of air-driven diaphragm, artificial hearts implanted with either cardiopulmonary bypass or deep hypothermia were studied in ten calves surviving beyond the initial effects of surgery (beyond 40 hours). Calves were maintained up to ten days with normal aortic blood pressures, but with elevated right ventricular and pulmonary artery pressures and gradually inceasing venous pressure, and symptoms of right artificial heart failure. Smooth, Silicone rubber-surfaced, artificial hearts produced less blood damage than rough-surfaced hearts of Dacron fibrils; however, there was greater evidence of embolization with the smooth hearts. Mock circulation studies indicate that an asynchronously beating atrium as occurs in the calf experiments can drastically reduce cardiac output Elimination of the high C-wave which occurs with the artificial heart could be demonstrated on the mock circulation with the use of an active valve. The major problem with the present artificial heart is postulated to be at the inflow. Asynchronously beating atria with high pressure pulses and compression of the artificial heart against the natural atria and inflow vessels severely decreases cardiac output