We investigated blood pressure (BP) and heart rate variability and baroreflex sensitivity (BRS) in white-coat, masked and sustained hypertension in untreated patients (n = 645). Normotension and white-coat, masked, and sustained hypertension were defined according to the clinic (cutoff 140/90 mmHg) and 24-h ambulatory (130/80 mmHg) BPs. The Finometer device recorded beat-to-beat finger BP and electrocardiograms in the supine and standing positions for the computation of frequency-domain power-spectral BP and heart rate variability indexes and BRS. In multivariate analysis, BP variability indexes in the supine position differed significantly (P < 0.0001) for both low-frequency (LF) and high-frequency (HF) components and the LF/HF ratio, with the lowest LF and HF power and highest LF/HF ratio in white-coat hypertension (n = 28), the highest LF and HF power and lowest LF/HF ratio in sustained hypertension (n = 198), and intermediate values in normotension (n = 189) and masked hypertension (n = 230). These differences diminished in the standing position, being significant (P < 0.0001) only for the LF component variability. The LF/HF ratio in BP in the supine position decreased with advancing age in normotension and sustained hypertension (P ≤ 0.03) but not white-coat or masked hypertension (P ≥ 0.12). For heart rate variability, a significant difference was observed only for the LF component in the supine position (P = 0.0005), which was lowest in white-coat hypertension. BRS in masked and sustained hypertension was significantly (P ≤ 0.0001) lower than that in normotension in both supine and standing positions and decreased with advancing age (P ≤ 0.0001). In conclusion, masked, but not white-coat, hypertension showed similar patterns of, but slightly less severe, changes in BP and heart rate variability and BRS to sustained hypertension.
Keywords: Autonomic nervous system; Masked hypertension; Sustained hypertension; White-coat hypertension.