Correlation between the severity of obstructive sleep apnea and heart rate variability indices.
The risk of cardiovascular disease is known to be increased in obstructive sleep apnea syndrome (OSAS). Its mechanism can be explained by the observation that the sympathetic tone increases due to repetitive apneas accompanied by hypoxias and arousals during sleep. Heart rate variability (HRV) representing cardiac autonomic function is mediated by respiratory sinus arrhythmia, baroreflex-related fluctuation, and thermoregulation-related fluctuation. We evaluated the heart rate variability of OSAS patients during night to assess their relationship with the severity of the symptoms. We studied overnight polysomnographies of 59 male untreated OSAS patients with moderate to severe symptoms (mean age 45.4+/- 11.7 yr, apnea-hypopnea index [AHI]=43.2+/-23.4 events per hour, and AHI >15). Moderate (mean age 47.1+/-9.4 yr, AHI=15-30, n=22) and severe (mean age 44.5 +/-12.9 yr, AHI >30, n=37) OSAS patients were compared for the indices derived from time and frequency domain analysis of HRV, AHI, oxygen desaturation event index (ODI), arousal index (ArI), and sleep parameters. As a result, the severe OSAS group showed higher mean powers of total frequency (TF) (p=0.012), very low frequency (VLF) (p= 0.038), and low frequency (LF) (p=0.002) than the moderate OSAS group. The LF/HF ratio (p=0.005) was higher in the severe group compared to that of the moderate group. On the time domain analysis, the HRV triangular index (p=0.026) of severe OSAS group was significantly higher. AHI was correlated best with the LF/HF ratio (r(p))=0.610, p<0.001) of all the HRV indices. According to the results, the frequency domain indices tended to reveal the difference between the groups better than time domain indices. Especially the LF/HF ratio was thought to be the most useful parameter to estimate the degree of AHI in OSAS patients.
Park
Doo-Heum
DH
Department of Psychiatry, Konkuk University School of Medicine, Seoul, Korea.
Shin
Chul-Jin
CJ
Hong
Seok-Chan
SC
Yu
Jaehak
J
Ryu
Seung-Ho
SH
Kim
Eui-Joong
EJ
Shin
Hong-Beom
HB
Shin
Byoung-Hak
BH
D000328:Adult; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000473:pathology; D004562:Electrocardiography / Q000379:methods; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000378:metabolism; D010991:Plethysmography; D017286:Polysomnography / Q000379:methods; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000473:pathology
D010100:Oxygen