Current status of the National Cardiovascular Center totally implantable artificial heart system

We have been developing an electrohydraulic total artificial heart (EHTAH) system. The system consists of diaphragm-type blood pumps, an electrohydraulic energy converter, an internal control unit, a transcutaneous energy transfer (TET) system, a transcutaneous optical telemetry (TOT) system, and an internal battery. The energy converter reciprocates and delivers hydraulic silicone oil to the alternate blood pumps. The displacement volume and the weight of the system are 872 ml and 2492 g, respectively. The maximum flow rate was 12 L/min and the maximum efficiency was 15.4%. The system performance was examined in a series of in vivo experiments. The system was successfully implanted in 16 calves in the range of 60 kg or more. Four of the 16 calves survived for more than 1 month approximately. One of them lived for 70 days. The system was basically driven by the TET system, and was driven by the internal battery for 40 minutes everyday. The internal battery was fully charged within 3 hours after usage. DC-DC transmission efficiency of around 80 % was maintained during operation with the TET system. These results indicate that EHTAH has the potential to be a totally implantable system.