Monitoring of the vegetative background of sleep by means of spectral analysis of heart rate variability

From the ECG trace of the sleep polygrams the heart rate variability (HRV) is derived by determining the intervals between the R peaks. During sleep, transitions of heart rate can be observed in HRV signal which are relevant to changes in the autonomic regulation. For better insight into the vegetative background of sleep, the spectrum analysis of HRV signal and its parameters has been calculated. In particular LF/HF (ratio between the powers in low frequency range over high frequency range) is considered the measure of sympatho/vagal balance. A trend of such a ratio is compared with the parameters obtained in different vegetative tests (Rest to Stand, Valsalva-maneuver etc.). The HRV signal showed characteristic patterns in the time and in the frequency domains in the different sleep states. The presented method offers a pronounced sensibility to explore the autonomic regulatory activities during sleep