Association Analysis Of Variability In Blood Pressure And Heart Rate

Variability of blood pressure and heart rate is an important quantitative tool to assess the autonomic activity. Because autonomic nervous system plays essential role in cardiovascular control and is related with a series of cardiovascular diseases, a lot of researches have been conducted in this area. However, due to the limitation of measurement techniques, current researches mostly focus on heart rate variability, and there are still ambiguity and inconsistency in the understanding and application of this spontaneous variability. Thus our study investigated the association between blood pressure and heart rate variability and intended to apply them to the estimation of autonomic control to cardiovascular system.In this study, clinical research was performed to analyze heart rate variability in people with normal, high normal and high blood pressure, in order to explore the alteration of autonomic control in hypertension and evaluate the practical significance of this variability. Meanwhile, animal experiments were employed to analysis association between blood pressure and heart rate variability;a radio telemetry system was applied to record ECG and blood pressure signals in rat, and receptor blockers of α-adrenergic, β-adrenergic and cholinergic receptors were treated to analyze autonomic influence on power spectrum of blood pressure and heart rate variability.In clinical study, heart rate variability show different patterns among normal people, subjects with high normal blood pressure and hypertensives. Heart rate variability parameters of subjects with high normal blood pressure and hypertensives were similar, and were different with those of normal people. After head-up tilt, hypertensives had smaller alteration of heart rate variability than the other two groups. In animal experiments, all receptor blockers altered blood pressure and heart rate variability significantly. Blockers of sympathetic nerve reduced the low frequencyband of blood pressure and heart rate variability. Parasympathetic Blockade decreased heart rate variability, but increased blood pressure variability.Based on these results, we conclude that: 1. This spontaneous variability has close relation with autonomic nervous system, however, it dose not indicate mean autonomic tone, but reflects the fluctuation and dynamic response of cardiovascular system, and may be affected by various factors, such as baroreflex sensitivity. 2. Parameters of heart rate variability can recognize subjects in different stages of hypertension and illustrate the alteration of cardiovascular control in the development of hyperternsion. 3. Heart rate variability is related to blood pressure variability as they both represent branches of autonomic nervous system, and this relation also reflects the baroreflex buffering of blood pressure fluctuation. Utilizing blood pressure and heart rate variability simultaneously will bring a better view of cardiovascular control activity.