Abstract:
:The recently-introduced technique of detrended fluctuation analysis (DFA) for heart-rate variability appears to yield improved prognostic power in cardiovascular disease through calculation of the fractal scaling exponent alpha. However, the physiological meaning of alpha remains unclear. In DFA, the signal is segmented into lengths from 4 to 64 beats. For each segmentation length (n), the individual segments are cumulated, detrended and the sum of the squares (F2) of residuals calculated. Alpha is the slope of log(F) against log(n). We show mathematical equivalence between alpha calculated by DFA and by a novel alternative method using frequency-weighted power spectra. We show F2 (and thus alpha) can be obtained from a frequency-weighted power spectrum without DFA. To do this, we cumulate and detrend the Taylor series of individual Fourier components. F2 is found to depend on the relationship between the signal period and segment length. F2 can therefore be expressed in terms of frequency-weighted power spectra. From this, the alpha coefficient of DFA can then be described in power-spectral terms, which facilitates exploration of its physiological basis. We confirm these findings using samples from 20 healthy volunteers and 40 patients with heart failure.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Willson K,Francis DP,Wensel R,Coats AJ,Parker KHdoi
10.1088/0967-3334/23/2/314subject
Has Abstractpub_date
2002-05-01 00:00:00pages
385-401issue
2eissn
0967-3334issn
1361-6579journal_volume
23pub_type
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pub_type: 临床试验,杂志文章
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