Modified scaled Fourier linear combiner in thoracic impedance cardiography.
New filtering algorithms; a modified scaled Fourier linear combiner (mSFLC) and a modified ensemble averaging (mEA) are proposed to remove the phase distortion of the impedance waveform caused by SFLC. Performance of the filters is assessed from the shape of the filtered waveform and the estimation of systolic time intervals. It was found that the mSFLC and mEA could compensate for drawbacks of the SFLC and precisely reproduce the impedance waveforms; however, misinterpretation and attenuation in the cardiac variables may be caused when abrupt changes or irregularities occur in the source waveform.
Ishiguro
Toshimichi
T
Health Science Center, Toyohashi University of Technology, Toyohashi, Japan.
Umezu
Akihito
A
Yasuda
Yoshifumi
Y
Horihata
Satoshi
S
Kardec Barros
Allan
A
D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001919:Bradycardia / Q000503:physiopathology; D002307:Cardiography, Impedance / Q000379:methods*; D004562:Electrocardiography; D005583:Fourier Analysis; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010701:Phonocardiography; D011187:Posture / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D013599:Systole / Q000502:physiology; D013610:Tachycardia / Q000503:physiopathology; D013997:Time Factors