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. 2012 Feb 22;3:34. doi: 10.3389/fphys.2012.00034

Figure 2.

Figure 2

Multiscale PDF characterization of heart rate variability. Illustrative examples of time series of NN intervals b(t) (A–D), time series of Δ20sB(i) (E–H), time series of Δ180sB(i) (I–L), and standardized PDFs (in logarithmic scale) of ΔsB(i) for (from the top to bottom) s = 20, 60, 180, 300 s (M–P), where σs denotes the SD of ΔsB(i). In solid lines, we superimpose the PDF approximated by Castaing’s model (Castaing et al., 1990). The panels on the leftmost side (A,E,I,M) are data for a 60-year-old male patient with multiple system atrophy (MSA). The panels on the left-of-center side (B,F,J,N) are data for a 68-year-old male patient with Parkinson disease (PD). The panels on the right-of-center side (C,G,K,O) are data for a 83-year-old female patient with congestive heart failure (CHF) who died 54 days after the measurement. The panels on the rightmost side (D,H,L,P) are data for a control subject (84-year-old male). For comparison, the dashed line denotes a Gaussian distribution. Note that, while the raw b(t) for the patients looks much different from that for the control subject, the degrees of non-Gaussianity (i.e., the shapes of PDF) remain unaltered across scales for MSA and PD patients and the healthy control, except for those for the CHF patient at shorter scales (G,O).