Title :
Multifractal analysis of the day and night characteristics of heart rate variability
Author :
Ramchurn, SK ; Murray, A.
Author_Institution :
Univ. of Mauritius, Reduit, Mauritius
Abstract :
The RR heart rate variability characteristics of normal subjects were studied to compare the multifractal characteristics during day and night. The RR intervals were obtained from 24-hour digital Holter ECG recordings of normal subjects, starting at midday. Each 24 hour period was split into 4 blocks of 6-hour which were analysed separately. The overnight period was fully contained in the third block, between midnight to 6 a.m. The 6-hour blocks were analysed using a wavelet transform multifractal formalism. Each spectrum peaked between the Hurst exponent (h) limits of 0.07 and 0.29. In one subject the overnight spectrum did not have a consistent overnight peak and could not be analysed. In the subjects with well-defined spectral peaks, the overnight peak position of h tended to be greater than that for any of the other three 6-hour periods, indicating that the fractal characteristics of the RR intervals differ during the overnight sleep period.
Keywords :
electrocardiography; fractals; medical signal processing; sleep; wavelet transforms; 24-hour digital Holter ECG recordings; Hurst exponent; RR heart rate variability characteristics; asleep states; awake states; day characteristics; multifractal characteristics; night characteristics; overnight period; overnight sleep period; wavelet transform multifractal formalism; Continuous wavelet transforms; Digital recording; Electrocardiography; Fractals; Heart beat; Heart rate variability; Hospitals; Signal analysis; Wavelet analysis; Wavelet transforms;
Conference_Titel :
Computers in Cardiology, 2002
Print_ISBN :
0-7803-7735-4
DOI :
10.1109/CIC.2002.1166799