Improvements of scale fourier linear combiner for impedance cardiography analysis

In this paper, we present two additions to the SFLC algorithm in order to improve the beat by beat estimation of fiducial points (B and X) and the maximum value of the derivative in impedance cardiography signal: addition of a reference input and scanning each beat more than once. On data synthesized from real ICG which exhibits beat by beat changes and baseline variations, we used statistical measures to show that the modified algorithms give accurate beat by beat estimation conversely to the original version of SFLC. We also give results on a real ICG using phono cardiography as a reference. In this case too, results show the pertinence of the proposed improvements.