Nocturnal heart rate variation in diabetic and non-diabetic patients with sleep apnea syndrome.
Heart rate variability (HRV) analysis is used for the evaluation of autonomic function in the cardiovascular system. Decreased HRV is associated with disorders affecting the autonomous system such as diabetes mellitus (DM) and obstructive sleep apnea (OSA). Previous studies have shown an association between OSA and DM. However, the interrelationships of HRV with OSA and DM are not well known. The aim of this study was to assess nocturnal HRV in patients who suffered from OSA with and without DM.



Sixty patients with OSA (27 with DM and 33 non-DM) underwent polysomnography for eight hours starting at midnight. From electrocardiogram (ECG) recordings taken as a part of polysomnography, time-domain and frequency-domain HRV parameters were evaluated to compare patients with regard to nocturnal HRV components such as low frequency (LF) and high frequency (HF), apnea-hypopnea index (AHI) and sleep parameters.



In the non-DM group, a direct relationship was observed between AHI and HRV rather than very low frequency (VLF) and LF/HF variables. This relationship was just significant between AHI and standard deviation of five-min average of normal R-R intervals and adjacent R-R intervals differing by 0.50 ms over 24 h (p < 0.05). In the DM group, the correlation between AHI and HRV parameters except HF and waking frequency was direct and non-significant. Intergroup comparison showed a significant difference between groups regarding AHI and HRV-index, LF and VLF (p < 0.05).



DM can affect HRV; however, this is not the case in OSA patients. This means that in the presence of OSA, the DM effect on HRV disappears.
Pulmonary Unit, Department of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran; Bamdad Respiratory Research Center, Isfahan, Iran. Electronic address: amra@med.mui.ac.ir.
Babak
B
Amra
Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Khorram Ave, PO Box 81465-1148 Isfahan, Iran. Electronic address: behjati@med.mui.ac.ir.
Mohaddeseh
M
Behjati
Center of Sleep Medicine, Charité - Universitätsmedizin Berlin, Charitéplatz 1, DE-10117 Berlin, Germany. Electronic address: thomas.penzel@charite.de.
Thomas
T
Penzel
Charité - Universitätsmedizin Berlin, Dept. of Cardiology and Pulmonology, Center of Sleep Medicine, Luisenstr. 13a, D-10117 Berlin, Germany. Electronic address: ingo.fietze@charite.de.
Ingo
I
Fietze
Charité - Universitätsmedizin Berlin, Dept. of Cardiology and Pulmonology, Center of Sleep Medicine, Luisenstr. 13a, D-10117 Berlin, Germany. Electronic address: Cristoph.Schoeble@charite.de.
Christoph
C
Schoebel
Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Khorram Ave, PO Box 81465-1148 Isfahan, Iran. Electronic address: nsarrafzadegan@gmail.com.
Nizal
N
Sarrafzadegan
D002319:Cardiovascular System / Q000503:physiopathology; D003920:Diabetes Mellitus / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D012891:Sleep Apnea Syndromes / Q000503:physiopathology*
Diabetes mellitus; Heart rate variability; Obstructive sleep apnea