Automatic Correction of Left-Ventricular Pressure Waveform Using the Natural Observation Method

Jun-ichi HORI  Yoshiaki SAITOH  Tohru KIRYU  Taizo IIJIMA  

IEICE TRANSACTIONS on Information and Systems   Vol.E75-D   No.6   pp.909-915
Publication Date: 1992/11/25
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Medical Electronics and Medical Information
automatic correction,  natural observation method,  catheter manometer system,  left-ventricular pressure waveform,  flushing device,  

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The pressure waveforms indicated on a catheter manometer system are subject to serious distortion due to the resonance of the catheter itself, or the compliance of a particular transducer. Although several methods have been proposed for improving those characteristics, they ahave never been put into practice. We have focused on the transfer function of the catheter manometer, and made a pilot system, using the natural observation method. This method has been suggested as a means of studying the structure of the instantaneous waveform. In this manner, we were able to increace the bandwidth in the ferquency domain and reduce the ringing in the time domain. Correction was performed automatically, using a step wave. Reproduction of the waveform with a flushing device, was a task of equal simplicity, that allowed us to estimate the system parameters so that the response waveform became step-like. In the experiment, our system provided distortion-free left-ventricular pressure waveform measurements and exact evaluation of the cardiac pumping system. The values obtained came much closer to the original figures arrived at by the catheter-tip manometer system.