Assessment of Baroreflex Sensitivity Using Time-Frequency Analysis during Postural Change and Hypercapnia

Figure 4

Exemplary representations of modulus of TF cross spectrum and TFCoh-TFPS/band binary masks for the same subject as in Figure 2 (postural change in normocapnia stage of the experiment). (a) Exemplary modulus of TF cross spectrum of pulse interval variability (PIV) and systolic arterial pressure variability (SAPV) signals. (b) Binary mask M_LF based on TFCoh-TFPS mask and instantaneous spectral peaks of TF cross spectrum in low-frequency band (0.04–0.15 Hz). (c) Binary mask M_HF based on TFCoh-TFPS mask and instantaneous spectral peaks of TF cross spectrum in high-frequency band (0.15–0.4 Hz). In (b) and (c), black areas denote parts of the representations used in BRS estimation.

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