Cardiac sympathetic modulation in response to apneas/hypopneas through heart rate variability analysis.
Autonomic dysfunction is recognized to contribute to cardiovascular consequences in obstructive sleep apnea/hypopnea syndrome (OSAHS) patients who present predominant cardiovascular sympathetic activity that persists during wakefulness. Here, we examined 1) the factors that influence sympathetic cardiac modulation in response to apneas/hypopneas; and 2) the influence of autonomic activity during apneas/hypopneas on CA. Sixteen OSAHS patients underwent in-hospital polysomnography. RR interval (RR) and RR spectral analysis using wavelet transform were used to study parasympathetic (high frequency power: HF(WV)) and sympathetic (low frequency power: LF(WV) and LF(WV)/HF(WV) ratio) activity before and after apnea/hypopnea termination. Autonomic cardiac modulations were compared according to sleep stage, apnea/hypopnea type and duration, arterial oxygen saturation, and presence of CA. At apnea/hypopnea termination, RR decreased (p<0.001) while LF(WV) (p = 0.001) and LF(WV)/HF(WV) ratio (p = 0.001) increased. Only RR and LF(WV)/HF(WV) ratio changes were higher when apneas/hypopneas produced CA (p = 0.030 and p = 0.035, respectively) or deep hypoxia (p = 0.023 and p = 0.046, respectively). Multivariate statistical analysis showed that elevated LF(WV) (p = 0.006) and LF(WV)/HF(WV) ratio (p = 0.029) during apneas/hypopneas were independently related to higher CA occurrence. Both the arousal and hypoxia processes may contribute to sympathetic cardiovascular overactivity by recurrent cardiac sympathetic modulation in response to apneas/hypopneas. Sympathetic overactivity also may play an important role in the acute central response to apneas/hypopneas, and in the sleep fragmentation.
Service de Physiologie Clinique, Pole NOL, CHU Nord, Saint-Etienne, France ; EA 4607 SNA-EPIS, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France.
Florian
F
Chouchou
Service de Physiologie Clinique, Pole NOL, CHU Nord, Saint-Etienne, France ; EA 4607 SNA-EPIS, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France.
Vincent
V
Pichot
Service de Physiologie Clinique, Pole NOL, CHU Nord, Saint-Etienne, France.
Jean-Claude
JC
Barthélémy
Unité NeuroPain, Centre de recherche en Neurosciences de Lyon, INSERM U1028 CNRS UMR5292, Lyon, France.
Hélène
H
Bastuji
Service de Physiologie Clinique, Pole NOL, CHU Nord, Saint-Etienne, France ; EA 4607 SNA-EPIS, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France.
Frédéric
F
Roche
D000368:Aged; D001049:Apnea / Q000503:physiopathology*; D001143:Arousal; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D017286:Polysomnography; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000209:etiology / Q000503:physiopathology; D012894:Sleep Stages; D013564:Sympathetic Nervous System / Q000502:physiology* / Q000503:physiopathology