Modeling baroreflex regulation of heart rate during orthostatic stress
Modeling baroreflex regulation of heart rate during orthostatic stress
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DOI：
10.1152/ajpregu.00205.2006
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发表时间：
2006-11-01
影响因子：
2.8
通讯作者：
Novak, Vera
中科院分区：
文献类型：
--
作者：
Olufsen, Mette S.;Tran, Hien T.;Novak, Vera
在体位应激期间，动脉和心肺压力反射通过调节心率在维持动脉压方面发挥着关键作用。这项研究提出了一个数学模型，可以预测心率调节响应从坐到站的姿势变化的动态。该模型使用手指测量的血压作为输入来模拟心率动态，以响应压力感受器神经放电频率、交感神经和副交感神经反应、前庭交感神经反射以及去甲肾上腺素和乙酰胆碱浓度的变化。我们制定了用于参数估计的逆最小二乘问题，并成功证明我们的数学模型可以准确预测从健康年轻人、健康老年人和高血压老年受试者获得的数据中观察到的心率动态。我们的主要发现之一表明，为了根据临床数据成功验证我们的模型，有必要包括前庭交感反射。此外，我们的模型表明，神经放电和血压之间的传递是非线性的，并且遵循滞后曲线。在健康的年轻人中，磁滞回线较宽，而在健康且患有高血压的老年人中，磁滞回线转向较高的血压值，并且其面积减小。最后，对于高血压老年人来说，滞后环通常不闭合，这表明在从坐姿到站立的姿势变化过程中，压力反射调节在站立的第一分钟内不会恢复到稳定状态。
During orthostatic stress, arterial and cardiopulmonary baroreflexes play a key role in maintaining arterial pressure by regulating heart rate. This study presents a mathematical model that can predict the dynamics of heart rate regulation in response to postural change from sitting to standing. The model uses blood pressure measured in the finger as an input to model heart rate dynamics in response to changes in baroreceptor nerve firing rate, sympathetic and parasympathetic responses, vestibulo-sympathetic reflex, and concentrations of norepinephrine and acetylcholine. We formulate an inverse least squares problem for parameter estimation and successfully demonstrate that our mathematical model can accurately predict heart rate dynamics observed in data obtained from healthy young, healthy elderly, and hypertensive elderly subjects. One of our key findings indicates that, to successfully validate our model against clinical data, it is necessary to include the vestibulo-sympathetic reflex. Furthermore, our model reveals that the transfer between the nerve firing and blood pressure is nonlinear and follows a hysteresis curve. In healthy young people, the hysteresis loop is wide, whereas, in healthy and hypertensive elderly people, the hysteresis loop shifts to higher blood pressure values, and its area is diminished. Finally, for hypertensive elderly people, the hysteresis loop is generally not closed, indicating that, during postural change from sitting to standing, baroreflex modulation does not return to steady state during the first minute of standing.