The importance of the very low frequency power of heart rate variability in screening of patients with obstructive sleep apnea

Sleep apnea is a complete or partial cessation of breathing during sleep. Obstructive sleep Apnea (OSA) is the common form of apnea that occurs when the upper airway is partially or completely obstructed due to the relaxation of dilating muscles. In developed countries the cost of investigating patients has increased considerably during the last decade as the only reliable method for the diagnosis of OSA until now is overnight sleep studies (Polysomnography), which is a cumbersome, time consuming and expensive procedure requiring specially trained polysomnographers and needs recording of ECG, EEG, EMG, EOG, nasal air respiratory effort and oxygen saturation.