engleski

"Memory effect" in heart rate dynamics

Specific changes in the structure of heart rate variability (HRV) pattern could be indicators for some pathological states of the heart. We have analysed those changes, in comparison with healthy subjects, in the case of stable angina pectoris (SAP), using the methods of nonlinear dynamics. Two complementary methods are used: the method of G-moments and the method of Rescaled range R/S analysis. These methods have been used previously for studying scaling behavior in multiparticle production processes (G-moments) and for studying water--level oscilations in hydrology (R/S analysis). The "memory effect", as a measure of the range of correlation in the time series is studied for beat-to-beat (RR) intervals. We have tested the possibility to distinguish healthy subjects from those with SAP. A good separation is achieved using the R/S method during the controled physical activities. Also, we have found an interesting correlation between RR and ST intervals. The results are only preliminary.

memory effect; heart rate variability

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