A new algorithm for the optimal operating point control in artificial hearts

A. Ishikawa, M. Yoshizawa, A. Tanaka, K. Abe, T. Yambe, S. Nitta

Research output: Contribution to journalArticlepeer-review

Abstract

The authors have previously shown that the desired value of stroke volume can be achieved with minimum driving energy by driving a sac-type air-driven artificial heart at the optimal operating point (OOP). When stroke volume is plotted against systolic duration, the resulting curve forms a triangle with the systolic duration axis as its base. The OOP is the operating point at the apex of the triangle and is opposite the base. The conventional algorithm for automatic maintenance of the OOP utilized the time (z[ms]) when the outflow rate (f(t)[L/min]) changes from positive to zero. This causes the following defects: 1) susceptibility to noise in the f(t); and 2) difficulty in determining the correction factor included in the algorithm. To overcome these defects, the present study proposes a new algorithm for determination of the OOP on the basis of the time (p[ms]) maximizing f(t) value during the same beat, instead of z. Experiments carried out in a mock circulatory system have shown that the new algorithm works in a satisfactory manner.

Original languageEnglish
Pages (from-to)527-533
Number of pages7
JournalJapanese Journal of Artificial Organs
Volume25
Issue number3
Publication statusPublished - 1996 Sep 11

Keywords

  • air-driven artificial heart
  • artificial heart
  • minimum driving energy
  • optimal operating point
  • robust algorithm

ASJC Scopus subject areas

  • Biophysics

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