EXTERNALLY-COUPLED TRANSCUTANEOUS ENERGY TRANSMISSION SYSTEM FOR A TOTALLY IMPLANTABLE ARTIFICIAL HEART-IN VITRO AND IN VIVO ESTIMATIONS FROM THE VIEWPOINT OF ELECTRICAL ENGINEERING

Abstract

Externally-coupled transcutaneous energy transmission system(ECTETS) which has DC to DC energy transmission efficiency of more than 86% in in vitro experiment is very useful for a totally implantable artificial heart. In in vivo experiment of the ECTETS with the internal coil and the rectifier circuit implanted under the skin of a living goat, the DC to DC energy transmission efficiencies were measured using electronic load simulator(ELS) and implantable electrohydraulic total artificial heart(EHTAH) as a load, respectively. As a result, the DC to DC energy transmission efficiency of the ECTETS with the ELS was 81.4% in operation at the output power of 19.2W. It was found that the lowering of the efficiency compared with that in in vitro experiment was caused by the increase in stray capacitance between the windings of the external coil by applying liquid to that surface for sterilization. In driving the EHTAH at the heart rate of 70bpm, the driving power was 20.7W, the pump output flow was 6.2L/min, the DC to DC energy transmission efficiency was 82.1%, and the surface temperature of the internal circuit was less than 40.5°C. In conclusion, the ECTETS had good performance in in vivo experiment.