Autonomic Dysfunction Increases Cardiovascular Risk in the Presence of Sleep Apnea

Figures

• 

  Figure 1. A flowchart of the data analysis performed for each subject is displayed. First, the modulating signal was divided in periods corresponding to NREM (black) and REM (gray) sleep. Afterwards, two different HRV analyses were performed in each of the sleep stages: one including the apneic episodes (red) and one excluding them (the 1-min period after the apneic episodes are included in the segments highlighted in red). The HRV analyses are performed over 5-min windows of available signal.

• 

  Figure 2. Average spectra for all the NREM segments (excluding those with apneic episodes) of a control subject of the UZ Leuven dataset (black) and his match (gray) are displayed. An increased sympathetic dominance can be noticed in the control subject, as reflected by the relative higher low frequency power content. The dashed black lines indicate the boundaries of the low frequency band. The number of averaged 5 min segments was 50 and 36 for the control and the match, respectively. As estimated from the modulating signal, the power spectral density is given in arbitrary units (a.u.).

• 

  Figure 3. Boxplots of the differences in mean NN (ΔNN) and PLFne (ΔPLFne) between the control subjects of the UZ Leuven dataset and their matches under or not under medication intake (during NREM sleep and excluding apneic episodes). Whereas, ΔNN is increased in the group under medication intake when compared to the group without medication (p < 0.05, indicated with *), no differences in ΔPLFne were assessed.