Quantitative analysis of the arterial baroreflex transient response during acute myocardial infarction toward optimized therapy

本研究旨在定量分析急性心肌梗死对心血管调节的影响，建立能够描述急性心肌梗死期间血流动力学变化的循环模型。利用该模型，可以通过模型参数的变化定量描述急性心肌梗死期间的血流动力学变化。这样的定量评价将有助于急性心肌梗死的风险分层。此外，通过对给药循环反应的预测，可优选出总用量最小的最佳给药方案。在本研究中，我们分别通过传递函数分析和平衡图分析来量化动脉压力反射的动态和静态特性。在麻醉的家兔中，苯基双胍激活迷走神经介导的心脏反射，大约使动脉压力反射减半。考虑到气压反射增益的预测变化，我们设计了一个自动药物输注系统。当使用具有固定参数值的经典比例-积分-导数（PID）控制器时，对给定剂量的药物的生物反应幅度的变化使循环调节不稳定。相比之下，具有神经网络的自适应预测控制器提供了稳定的循环调节，而不受给定剂量药物的生物反应变化的影响。虽然研究了急性冠状动脉闭塞对动脉压力反射的影响，但即使出现低血压和泵衰竭，其动态特性也没有明显变化。冠状动脉闭塞对压力反射增益没有显著影响的可能解释可能是由于麻醉条件下迷走神经戒断导致迷走神经介导的心脏反射缺失。少

The present study was designed to quantitatively analyze the effects of acute myocardial infarction on the cardiovascular regulation and to develop a circulatory model capable of describing hemodynamic changes during acute myocardial infarction. By using this model, hemodynamic changes during acute myocardial infarction may be described quantitatively in terms of changes in model parameters. Such a quantitative evaluation would contribute to a risk stratification of acute myocardial infarction. In addition, the prediction of the circulatory responses to drug administrations would lead to the optimized drug administrations with tide minimum total amount of drug used. In the present study, we quantified the dynamic and static characteristics of the arterial baroreflex by a transfer function analysis and an equilibrium diagram analysis, respectively. In anesthetized rabbits, activation of the vagally-mediated cardiac reflex by phenylbiguanide approximately halved the arterial baroreflex g … More ain calculated from changes in sympathetic nerve activity relative to the pressure changes. We designed an automated drug infusion system by taking into account the predicted changes in the baroreflex gain. When a classical proportional-integrative-derivative(PID) controller with fixed parameter values was used, changes in the magnitude of biological responses to a given amount of drug makes the circulatory regulation unstable. In contrast, an adaptive predictive controller with a neural network provided a stable circulatory regulation regardless of changes in the biological responses to a given amount of drug. Although the effects of acute coronary occlusion on the arterial baroreflex were examined, changes in the dynamic characteristics were not significant even when hypotension with pump failure manifested. Possible explanation for the absence of significant effects of coronary occlusion on the baroreflex gain might be an absence of vagally-mediated cardiac reflex due to vagal withdrawal under anesthetic conditions. Less