Estimation of left ventricular recovery level based on the motor current waveform analysis on circulatory support with centrifugal blood pump

In a mock circulatory loop simulating the left heart bypass using a centrif ugal blood pump, analysis of the motor current waveform of the centrifugal pump was performed to derive a useful parameter to evaluate the status of v entricular function. The relationship between the peak, amplitude, and the peak of the fundamental frequency of the power spectral density of the peri odic motor current waveform (MCpsdP) that reflected the pulsatile ventricul ar pressure, and the peak of the left ventricular pressure (LVP) was examin ed. Although both peak and amplitude of the motor current waveform showed a n excellent correlation with the peak LVP, they failed to predict the openi ng of the aortic valve. The MCpsdP that corresponds to the frequency of the heart rate showed an excellent correlation with the peak LVP throughout th e LVP levels, but the slope between them changed with the opening of the ao rtic valve. Thus, it is possible to follow the change in the LVP and detect even the opening of the aortic valve, and, hence, the recovery of the left ventricle. However, the slope of the linear regression equation varied, de pending on the pump speed. This result implies that the MCpsdP can be possi bly used to follow the change of ventricular function during circulatory as sistance with a centrifugal blood pump as well as to control the pump speed in response to varying ventricular function.