Sensorless controlling method for a continuous flow left ventricular assist device

Artif Organs. 2000 Aug;24(8):600-5. doi: 10.1046/j.1525-1594.2000.06585.x.

Abstract

We originated a novel control strategy for a continuous flow left ventricular assist device (LVAD). We examined our method by acute animal experiments to change the left ventricular (LV) contractility or LV end-diastolic pressure (LVEDP). To estimate the pump pulsatility without any specific sensor, we calculated the index of current amplitude (ICA) from motor current waveform. The ICA had a peak point (t-i point) that corresponded closely with the turning point from partial to total assistance, and a trough (s-i point) that corresponded with the beginning point of ventricular collapse. The pump flow at the t-i point (Qt-i) had no component of flow regurgitation. In the evaluation of the effects of preload LVEDP, afterload (mAoP), and contractility (max LV dp/dt), we found that preload was the only parameter that significantly influenced Qt-i. We concluded that our method could well control continuous flow LVAD by preventing reversed flow and ventricular collapse.

MeSH terms

  • Animals
  • Centrifugation
  • Dogs
  • Heart-Assist Devices*
  • Hemodynamics
  • Hemorheology
  • Pulsatile Flow