The Effect of Baroreflex Function on Blood Pressure Variability

Objective: The aim of this study was to assess the relationship of blood pressure variability (BPV) and heart rate variability (HRV) to investigate the effect of baroreflex function on blood pressure variability. Methods: This study consisted of 111 subjects, including 32 normotensives and 79 hypertensives. All the subjects were given two concurrent tests: 24-hour Holter ECG and ambulatory blood pressure monitoring. According to standard deviation of normal-to-normal sinus RR intervals (SDNN) derived from the Holter ECG, the hypertensives were divided into two groups: an HRV normal group with SDNN > 100 ms and an HRV abnormal group with SDNN < 100 ms. HRV analysis used the time domain measure SDNN and two frequency domain analyses using low-frequency and high-frequency power. BPV analysis involved a formula correlated to each blood pressure value. Results: BPV was significantly higher in the HRV abnormal group compared with the HRV normal group in the hypertensives (0.018 ± 0.0033 vs 0.014 ± 0.0032, P < 0.05). In the HRV abnormal group, BPV value of the older hypertensive participants was higher than the younger participants (0.019 ± 0.0024 vs 0.017 ± 0.0037, P = 0.048). BPV and HRV were correlated in the younger hypertensives (r = ﹣0.314, P < 0.05) and older hypertensives (r = ﹣0.692, P < 0.001). Conclusions: Baroreflex function had effect on BPV. Factors like aging could cause damage to the baroreflex sensitivity, which in turn had influence on BPV. There may be benefits in restoration of baroreflex function to reduce BPV, especially in hypertensive patients.