Fig. 6From: Assessment of autonomic function by long-term heart rate variability: beyond the classical framework of LF and HF measurementsEstimation of apnea-hypopnea index (AHI) of polysomnography by the frequency of CVHR (Fcv) obtained from ECG R-R interval in 862 consecutive subjects with suspected sleep-disordered breathing. Modified Fig. 4 of reference [67]Back to article page