COMPARISON OF STANDARD AUTONOMIC TESTS AND POWER SPECTRAL-ANALYSIS INNORMAL ADULTS

Standard autonomic measures [heart rate response to deep breathing (HR (DB)), systolic blood pressure response to orthostatic load, the 30: 1 5 ratio, and the Valsalva ratio (VR)] and spectral measures of the hea rt rate (HR) and the arterial blood pressure (ABP) (MF: mid-frequency band at 0.05-0.15 Hz; HF: high-frequency band at 0.15-0.33 Hz) were pe rformed in 50 healthy subjects. The supine HR-HF and the tilt ABP-MF w ere taken as indicators of parasympathetic and sympathetic outflow, re spectively. The transfer function magnitude of HR related to the ABP i n the mid-frequency band estimated the baroreflex sensitivity. The HR( DB) and the 30:15 ratio were correlated with the parasympathetic spect ral measure, and the VR was, surprisingly, only correlated with the sy mpathetic spectral measure, Significant baroreflex contribution was on ly evident for the 30 : 15 ratio. The spectral HR data were highly cor related with their corresponding spectral data of ABP. These results p rovide insights into autonomic regulation, but further studies on both basic physiological mechanisms of these methods and their clinical va lue have to be performed before a broad application can be recommended . (C) 1996 John Wiley & Sons, Inc.