Cardiac dysautonomia and arterial distensibility in essential hypertensives

Abstract

Introduction The central nervous system plays an important role in the regulation of blood pressure: the sympathetic nervous system may be a primary contributor to the development of some forms of essential hypertension. Hypertension is also associated with reduced distensibility of large arteries. The aim of our study is the evaluation of a correlation between cardiac dysautonomia (evaluated by means of heart rate variability [HRV]) and altered artery distensibility (evaluated by means of measurement of the time interval from the onset of the QRS wave and the detection of the last Korotkoff sound [QKD interval]). Materials and methods HRV and QKD interval were evaluated in 23 patients (60.9 ± 8.7 years) with untreated hypertension and in 20 control subjects (53.2 ± 16.8 years). QKD interval and QKD 100–60 (that is QKD for a 100 mm Hg systolic blood pressure and 60 bpm heart rate) were measured during a 24-hours blood pressure monitoring. HRV was evaluated by means of a spectral method. Three main spectral components were distinguished: very low frequency (VLF), low frequency (LF) and high frequency (HF) component. Results Patients with reduced QKD 100–60 interval show reduced total power and spectral components values, with higher LF/HF ratio in basal conditions in comparison with control group. In patients with hypertension, QKD 100–60 values correlated significantly with LF/HF ratio (Spearman r = − 0.551; p = 0.006), HF spectral component (Spearman r = 0.630; p = 0.001) and total power (Spearman r = 0.426; p = 0.004). Conclusions Our results suggest that sympathetic overactivity may be the contributor of reduced arterial distensibility observed in patients with essential hypertension.