Correction of Pressure Waveforms in a Catheter Manometer System by Natural Observation Method

Pressure waveforms obtained by catheter manometer systems are often distorted by resonance of catheter and so on. Corrections by Fourier analysis, low pass filter and digital signal proccessing have been reported, but they have never been put to practical use. We paid attention to the transfer function of catheter transducer systems and made a trial system that correct the distortion by natural observation method. This system increases the bandwidth in frequency domain and reduce the ringing in time domain. Advantages of this system are simple composition, a small number of adjusting points and real time performance without modifying the catheter or transducer. In an animal experiment, we corrected by our trial system the output waveforms recorded by a conventional catheter manometer system and compared these corrected output waveforms with catheter-tip manometer waveforms which are relatively distortionless. As a result, we could obtain less distorted pressure waveforms in left-ventricle and aorta and distinctly confirm dicrotic notch in aortic pressure waveforms