Authors: Rodion Stepanov (rodion@icmm.ru), Sergey Podtaev, Andrey Dumler, and Sergey Chugainov Affiliations: Institute of Continuous Media Mechanics, Ak. Kororlev str. 1, 614013 Perm, Russia; Department of Introduction on Internal Diseasis, Perm State Medical Academy, Perm, Petropavlovskaya str. 26, Perm 614990, Russia. Abstract: Background: Impedance cardiography (ICG) is an inexpensive, noninvasive technique for estimate hemodynamic parameters. ICG can be used to obtain left atrial ejection fraction and monitoring systolic time intervals. Traditional ICG technique does not enable unambiguous detection of the left ventricle ejection time (LVET) and the time relationships between specific marker points. Objective: This work aims to approbate new approach for ICG signal processing using wavelet transform (WT) and to investigate the possibilities of this apporach for determination of the parameters which are related to the stroke volume (SV), in particular LVET. Methods: Thoracic tetrapolar polyrheocardiography method for simultaneous registration ECG, ICG and phonocardiogram have been used. Control group consists of eight healthy men of 20 to 25 years old. Also four patients with the diagnosis of the essential hypertension participated in the study. Wavelet representation of the ICG data produces the local maxima in two dimential distribution of the wavelet coefficient. Each extremum point is characterized by the amplitude, scale and time which determine SV. Results: LVET is suggested to define as the scale corresponding to the E-wave maximum, related to the systolic phase of the cardiac cycle. Also we defined initial systolic time interval (ISTI) as the time interval between R peak in the ECG and E-wave maximum on the wavelet plane. During functional test LVET and ISTI values, defined by WT, demonstrate a proper hemodynamic response to loading for the control group and patients with the essential hypertension. Conclusion: The proposed approach demonstrates the ability of ICG - WT technique for adequate assessment of SV parameters, including cardiac time intervals. Keywards: impedance cardiography, wavelet transform, hemodynamic parameters.