The Coefficient of Variation of RR Intervals (CVRR) on Electrocardiogram in Patients with Essential Hypertension with Reference to Aging, Hemodynamics and Sympatho-Adrenomedullary Function

To evaluate the significance of parasympathetic nerve activity in essential hypertension, we measured the coefficients of variation of RR intervals (CVRR) on electrocardiogram and examined the relationships between CVRR and aging, hemodynamics and sympathoadrenomedullary function in normotensive subjects (NT) and in patients with essential hypertension (EHT). Mean arterial pressure (MAP), heart rate (HR), plasma noradrenaline concentration (pNA), plasma adrenaline concentration (pAd) and CVRR resting in a supine position were simultaneously measured in 37 NT (33.8±2.0 years) and 47 mild-to-moderate EHT (51.3±1.5 years). In both NT and EHT, significantly negative correlations between CVRR and age (NT: r=-0.54, p