deBoer R W, Karemaker J M, Strackee J
Am J Physiol. 1987 Sep;253(3 Pt 2):H680-9. doi: 10.1152/ajpheart.1987.253.3.H680.
A beat-to-beat model of the cardiovascular system is developed to study the spontaneous short-term variability in arterial blood pressure (BP) and heart rate (HR) data from humans at rest. The model consists of a set of difference equations representing the following mechanisms: 1) control of HR and peripheral resistance by the baroreflex, 2) Windkessel properties of the systemic arterial tree, 3) contractile properties of the myocardium (Starling's law and restitution), and 4) mechanical effects of respiration on BP. The model is tested by comparing power spectra and cross spectra of simulated data from the model with spectra of actual data from resting subjects. To make spectra from simulated data and from actual data tally, it must be assumed that respiratory sinus arrhythmia at rest is caused by the conversion of respiratory BP variability into HR variability by the fast, vagally mediated baroreflex. The so-called 10-s rhythm in HR and BP appears as a resonance phenomenon due to the delay in the sympathetic control loop of the baroreflex. The simulated response of the model to an imposed increase of BP is shown to correspond with the BP and HR response in patients after administration of a BP-increasing drug, such as phenylephrine. It is concluded that the model correctly describes a number of important features of the cardiovascular system. Mathematical properties of the difference-equation model are discussed.
开发了一种心血管系统逐搏模型，用于研究静息状态下人类动脉血压（BP）和心率（HR）数据的自发短期变异性。该模型由一组差分方程组成，代表以下机制：1）压力反射对心率和外周阻力的控制；2）体循环动脉树的风箱特性；3）心肌的收缩特性（斯塔林定律和恢复）；4）呼吸对血压的机械影响。通过将模型模拟数据的功率谱和互谱与静息受试者实际数据的谱进行比较来测试该模型。为了使模拟数据和实际数据的谱相符，必须假设静息时的呼吸性窦性心律失常是由快速的、迷走神经介导的压力反射将呼吸性血压变异性转化为心率变异性所致。心率和血压中所谓的10秒节律表现为一种共振现象，这是由于压力反射交感神经控制回路中的延迟所致。模型对施加的血压升高的模拟反应显示与给予升压药（如去氧肾上腺素）后患者的血压和心率反应相对应。得出的结论是，该模型正确地描述了心血管系统的一些重要特征。讨论了差分方程模型的数学特性。
