Background: It has been well established that hypertension is associated with autonomic dysregulation. Studies investigating HRV have established that hypertension is characterized by sympathetic overactivity and or attenuation of parasympathetic modulation of the heart.
Methods: We examined short-term heart rate variability (HRV) as well as conventional indices of cardiovascular autonomic function including heart rate variation during deep breathing (HRVdb), 30: 15 ratio, pressor response to quiet standing and isometric handgrip in 35 male subjects (39 +/- 7 year, mean +/- SD) with new-onset hypertension (resting BP 155 +/- 17/101 +/- 8 mm Hg) and 17 age-matched normotensive men (resting BP: 111 +/- 7/71 +/- 5 mmHg).
Results: HRVdb was significantly lower in hypertensives (21 +/- 8) compared to normotensives (mean age 36 +/- 7, P = 0.03). Differences in mean RR were insignificant, logarithm of high-frequency (HF) spectral power of RR intervals was significantly lower in hypertensives compared to normotensives in the supine position (P = 0.02).
Conclusions: Our data suggest that new-onset hypertension is characterized by diminished short-term HRV, possibly due to an increase in cardiovascular sympathovagal balance.