Heart rate variability in white-coat hypertension

Area of Science:

• Cardiology
• Autonomic Nervous System Function
• Hypertension Research

Background:

• Essential hypertension and white-coat hypertension are distinct conditions affecting blood pressure regulation.
• Heart rate variability (HRV) is a non-invasive measure of autonomic nervous system activity.
• Understanding HRV in hypertensive states can offer insights into cardiovascular pathophysiology.

Purpose of the Study:

• To compare heart rate variability (HRV) between patients with essential hypertension, white-coat hypertension, and normotensive controls.
• To explore the relationship between HRV parameters and vasoactive hormones in these groups.

Main Methods:

• HRV was assessed at rest, during standing, and controlled forced breathing in 19 essential hypertensive, 8 white-coat hypertensive, and 13 normotensive individuals.
• Power spectral density analysis using Fourier transformation was employed to calculate HRV.
• Baseline plasma renin concentration was measured.

Main Results:

• Controlled breathing induced a smaller decrease in low frequency (LF) variation in hypertensive patients compared to normotensive controls (P=0.03).
• The reduction in LF/high frequency (LF/HF) ratio during controlled breathing was significantly different between hypertensive and normotensive groups (P=0.037).
• A positive correlation was observed between resting plasma renin concentration and both LF and LF/HF parameters (r=0.330, P=0.037 and r=0.378, P=0.016, respectively).

Conclusions:

• Observed HRV differences suggest impaired autonomic challenge responsiveness in essential hypertension.
• HRV spectrum analysis did not differentiate white-coat hypertension from essential hypertension or normotension.
• These findings contribute to understanding autonomic dysfunction in hypertension.