Research Article
Application of the Lomb-Scargle Periodogram to InvestigateHeart Rate Variability during Haemodialysis
Figure 6
Comparison of spectral parameters over the first 80 minutes (a short time duration is presented for clarity) of haemodialysis. Data points are centred within valid five-minute segments extracted from the RR interval tachogram, with the same segment being preprocessed by five different methods (CSI and “rules” based editing methods are included for illustration as their distorting effects are less apparent with real data). Only two PSD estimates (4th and 10th) are based on RR tachograms without any suspect data points, and these are shown by the arrows in the lower pane. (a) LF (nu) results during HD treatment. (b) HF (nu) results during HD treatment. (c) LF/HF (nu) results during HD treatment.
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