In obstructive sleep apnea, pronounced sleep fragmentation (arousal index) was independently associated with higher nocturnal HRV (coef 0.42, P=0.002), whereas OSA severity and hypoxemia were not.
Cross-Sectional
In patients with obstructive sleep apnoea, pronounced sleep fragmentation is independently associated with higher nocturnal heart rate variability and sympathetic dominance, whereas OSA severity and nocturnal hypoxaemia are not.
Effect estimate: coef 0.42
p-value: p=0.002
BACKGROUND: Obstructive sleep apnoea (OSA) results in sympathetic overdrive. Increased nocturnal heart rate variability (HRV) is a surrogate marker of autonomic disturbance. The aim was to study the association of the apnoea-hypopnea index (AHI), nocturnal hypoxaemia, and sleep fragmentation with nocturnal HRV to address the pathophysiological mechanisms underlying autonomic disturbance in OSA. METHODS: Participants of the Sleep Hearth Health Study with available data on nocturnal HRV and an AHI ≥10/h have been included in this cross-sectional analysis. The main outcome of interest was the association of sleep fragmentation, nocturnal hypoxaemia, and the AHI with nocturnal HRV. Multivariate regression modelling with the mean of the standard deviations of normal-sinus-to-normal-sinus-interbeat intervals in all 5-minute segments (SDNNIDX) and with low to high frequency power-ratio (LF/HF) as dependent variables controlling for prespecified confounders (age, sex, cups of coffee, beta blocker, nocturnal heart rate) was used to assess the contribution of the arousal index, total sleep time with an oxygen saturation <90% (TST90) and the AHI not due to arousals to HRV. The significance level was set at P<0.01. RESULTS: , median (IQR) AHI 18.6/h (14.0-25.6), the arousal index (coef =0.42, P=0.002) was independently positively associated with SDNNIDX also after having controlled for potential confounders, whereas the AHI (coef =0.22, P=0.030) and TST90 (coef =0.36, P=0.054) were not. The arousal index-but not TST and AHI-was also independently associated with LF/HF. CONCLUSIONS: In OSA, pronounced sleep fragmentation is associated with higher nocturnal HRV and a sympatho-vagal imbalance with sympathetic dominance. OSA severity and nocturnal hypoxaemia did not independently predict nocturnal HRV.
Bradicich et al. (Thu,) conducted a cross-sectional in Obstructive sleep apnoea (OSA). Sleep fragmentation, nocturnal hypoxaemia, and AHI was evaluated on Association of sleep fragmentation, nocturnal hypoxaemia, and the AHI with nocturnal HRV (SDNNIDX and LF/HF) (coef 0.42, p=0.002). In obstructive sleep apnea, pronounced sleep fragmentation (arousal index) was independently associated with higher nocturnal HRV (coef 0.42, P=0.002), whereas OSA severity and hypoxemia were not.
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