Recent progress on the vibrating flow pump as a totally implantable ventricular assist device

This study describes the present state of progress in the development of th e vibrating flow pump (VFP) ventricular assist system. We have proceeded wi th development aiming at a totally implantable ventricular assist system wi th smaller size and lighter weight appropriate for Asians like the Japanese by increasing the drive frequency. An actuator is important for the develo pment of the miniature sized and lightweight artificial heart. We applied a linear motor for the mechanical part at first. The step motor was applied after that. This form may be best if we want the lightweight small sized mo tor for an actuator. The cross slider form is applied at present. It succee ded in the miniaturization compared with the linear motor. In the VFP-type ventricular assist system, the blood contact parts are a central vibration tube with inflow and outflow chambers. We designed round diaphragms to prev ent thrombus formation. In addition, we developed an energy transmission sy stem for total implantation. The VFP creates a high frequency oscillated bl ood flow. It has a unique flow pattern. Brain blood flow increased although the total flow of the circulation did not change in the frequency of 25 to 30 Hz. The quantitative evaluation of the autonomic nerve function during the left heart assistance with an oscillated blood flow was carried out by spectral analysis. Some influences on an autonomic nerve were observed by t he VFP left heart assistance. We will continue development research with th e aim of clinical application.