| non-stop materials submission . | Ðóññêîÿçû÷íàÿ âåðñèÿ |
|
|
 |
|
|
|
HRV congress | General | Scientific | Clinical | Education | Useful |
|
|
L.A. Manilo; N.I. Rodina
St. Petersburg State University of Electrical Engineering, ul. Professora Popova 5, St. Petersburg, 197376 Russia
e-mail: lam@biosignal.ru
Introduction. The methods of the automatic analysis of the heart rate variability (HRV) find application in investigations of the activity of different physiological systems which control the heart functioning. The basic method for the estimation of the impact physiological factors is the spectral analysis of rhythmograms obtained in the processing of the electrocardiosignal. It is generally accepted in standard methods to measure the signal power on the short records of ECG in the following frequency ranges: VLF, LF and HF and to carry out the current analysis of its variation in time. Considering the interconnection of the function of the autonomous component of the activity and succession of the cardiac events, a mathematical model called the integral pulse frequency modulator (IPFM) was studied.
Objectives of this research are to study methods of continuous representation of autonomic control activity function for spectral analysis.
Materials and methods. Accurate power estimation depends on method of continuous representation of heart rate. In this paper three methods providing the best way representation of continuous function and sampling are studied: 1) linear interpolation, 2) cubic interpolation, 3) integral function restored by cubic interpolation.
The output signal from IPFM model comprises a train of impulse functions (Dirac's delta functions). Each impulse accords with QRS complex from the electrocardiosignal. The impulse train is transformed to array of intervals between two nearest impulses. Then representation of continuous function by one of the three methods takes place. Linear and cubic interpolation are performed for reciprocals of intervals (heart rates).
Results. Spectra evaluated by fast Fourier transform were compared by such index as leakage rate. It's defined as a measure of total leakage spectral components with respect to whole components. Experimental results shows the best method is representation by integral function restored by cubic interpolation.
Conclusion. To obtain cardiac event series IPFM model was used. It takes into account the physiological nature of information transmitted to the pacemaker, and its coding in the sequence of the cardiac events which is great importance in the recognition of the spectral components of the function of the cardiac rhythm control. [an error occurred while processing this directive]
