PRACTICAL IMPLEMENTATION OF IMPEDANCE REOGRAPHY IN CARDIOLOGY – NEW APPROACHES

Abstract

Background: The impedance rheocardiography is a simple, inexpensive, noninvasive method of assessment of central hemodynamics that can be used for detection of cardiovascular remodeling and thus promote an improvement of cardiovascular mortality. Modern mathematical methods of data management could help to discover new possibilities of rheographic signal analysis. Aim: To demonstrate the potential of a wavelet-analysis of rheocardiograms for identification of myocardial remodeling of patients with cardiovascular disorders. Materials and methods: The proposed method was validated in 12 healthy men aged from 20 to 25 years and 14 patients with arterial hypertension. We used a polyreocardiograph, which records simultaneously the impedance (ICG), the electrocardiogram (ECG) and the phonogram (PCG). The function of the cardiovascular system was assessed based on the two-dimensional time-frequency distributions of wavelet transformed coefficients of differential rheogram curves. Results: The results of an isometric load test confirm the adequacy of stroke volume estimation based on the amplitude of wavelet coefficients and the scale of the E wave. In this technique, ISTI parameter was defined as the time interval between the R wave in the ECG and the maximum of the E wave in the wavelet image. The simultaneous time-frequency analysis of both the pulse and respiratory component of an ICG signal can be a basis for the development of complex functional respiratory tests. Conclusion: The approach proposed demonstrates the possibility to obtain the characteristics of the diastolic phase of the cardiac cycle, and allows for a more precise determination of the stroke volume. Data management is done automatically. These advantages are expected to be used for producing a mobile cardiograph for screening diagnostic.

Keywords

• rheocardiography impedance
• phonocardiography
• stroke volume
• wavelet analysis