R&D engineering in cardiometry. Рубрика в журнале - Cardiometry
Статья научная
Aims The present paper aims at evaluating the existing difference in duration measurements of the same heart cycle phases in the standard V3, V4, V5, V6 leads ECG versus original HDA lead ECG of the ascending aorta. Materials and The method of changing the filter pass band is used. Its essence is in methods artificial changing of the conditions of the signal recording carrying the informative indications of the initial information used in hemodynamic equations. The method also enables calculating the percentage deviation from the initial values. The principle of balance of the blood volume entering the heart and the blood volume leaving the heart is used to trace the minimal deviations and their respective recording conditions. Results In each of the V3, V4, V5, V6 ECG leads durations of the same phases have different values. The values measured on the ECG of the ascending aorta and those measured using the standard V4 ECG lead differ slightly. Conclusion For heart cycle phase analysis it is possible to use only the ECG of the ascending aorta and V4 standard lead ECG. Using conventional standard ECG leads causes an error up to 25%.
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Criteria of identification of individual heart cycle phases on ECG
Статья научная
Aims Criteria of identification of individual heart cycle phases according to an ECG curve are described in this paper. Materials and For this study, a single-lead system ECG is used only. Its distinctive methods feature is that an ECG signal is recorded within the body surface area of the ascending aorta. Using the theory of biological system process continuity, the individual heart cycle phase boundaries are determined at those points of the cardiac signals where we deal with an energy process transition in the cardiovascular system from the process of the energy build-up to its attenuation, and vice versa. The transition points are identified by us by mathematical differentiation of the ECG signals, and, as a result, they correspond to extrema of the ECG derivative. Some individual heart cycle phases are found according to maxima on the derivative, others are identified according to minima on the derivative curve, respectively. Results The method of application of the ECG derivatives allows to capture individual heart cycle phases in a very precise manner. Utilization of the ECG derivatives is a prerequisite for computer-assisted processing of the data to deliver measurements of durations of every heart cycle phase. Conclusion Using the ECG derivatives for fixing every heart cycle phase makes possible to fill up the gaps in the theory of phase analysis and avoid misinterpretations of any type of the ECG phase structures.
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Статья научная
Aims This paper treats general problems of metrology and indirect measurement methods in cardiology. It is aimed at an identification of error estimation criteria for indirect measurements of heart cycle phase durations. Materials and A comparative analysis of an ECG of the ascending aorta recorded with the methods use of the Hemodynamic Analyzer Cardiocode (HDA lead) versus conventional V3, V4, V5, V6 lead system ECGs is presented herein. Criteria for heart cycle phase boundaries are identified with graphic mathematical differentiation. Stroke volumes of blood SV calculated on the basis of the HDA phase duration measurements vs. echocardiography data are compared herein. Results The comparative data obtained in the study show an averaged difference at the level of 1%. An innovative noninvasive measuring technology originally developed by a Russian R & D team offers measuring stroke volume of blood SV with a high accuracy. Conclusion In practice, it is necessary to take into account some possible errors in measurements caused by hardware. Special attention should be paid to systematic errors.
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Статья научная
Aims The article aims at describing the basic principles of cardiometry - a fundamentally new scientific field which enables the accurate measurement of cardiovascular system parameters. Materials and Cardiometry is based on the mathematical model of hemodynamic methods processes. The model is described by G. Poyedintsev and O. Voronova equations. The variable values in these equations are the cardiac cycle phase durations recorded on the ECG. Results An innovative mathematical model of hemodynamics providing the creation of an innovative indirect method of cardiovascular system parameters measurement was developed. The ECG processing is performed by means of the wavelet transform for detecting the boundaries of the cardiac cycle phases. Conclusion The innovative method of cardiovascular system diagnostics enables to measure 7 main hemodynamic parameters using noninvasive technology for qualitative evaluation of 12 functions of cardiovascular system performance and general assessment of coronary flow status. One of the problems the model of hemodynamics deals with is identifying the boundaries of the cardiac cycle phases. To identify the boundaries of the cardiac cycle phases the method of finding the extrema on the initial ECG and the differentiated ECG basing on the wavelet transform was used.
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