心血管系统建模

1、心血管系统建模心血管系统建模生物医学工程 07硕士 付秀泉人体循环系统组成n心脏n动脉n静脉n外周血管网络外周循环系统体循环动脉细动脉毛细血管细静脉静脉左心室右心房脉管模型重要参数n阻抗：血液在血管中流动时因其粘滞性而 受到的阻力血管对流动血液的相对阻抗脉管模型重要参数n容积：血管的弹性令它在受到透壁压的时 候发生舒张，改变容积PVC电路模型类比血管模型电路模型血流阻尼R = P/Q电阻 R血流 Q电流 i血压 P电压 e体积 V电荷 q血管容积 C = V/P电容C = q/e体循环的集中参数模型集中参数模型典型值Ca2 ml/mmHgCv100 ml/mmHgRa1 mmHg/ml/sec

2、Rv0.06 mmHg/ml/sec下标 a：动脉V：静脉Pa：动脉透壁压PV：静脉透壁压Pf：心房灌注压假设血流为0，出现一个系统平均填充压PmsPa = Pv = Pf = PmsCt为系统总容积Pms =(Vt V0)/Ct)(VaaaVCCCRRPfPmsQWindkessel简化模型 如果我们把注意力限制在大动脉上，并认为静脉的压力是常量，并近似为0，那么可以把外周循环简化为Windkessel模型。V：左心房每搏量 T：心跳周期心室模型D1：房室瓣D2：心室-大动脉瓣)()()(tCvVdtVtP心室压力-容量关系恒定的前端负载和后端负载与大动脉相连心-肺泵单元 右心 左心完整心血

3、管系统电路模型 右心 肺循环 左心体动脉Pth：胸内压 体静脉研究动态n联合助搏器测试的心血管仿真n左心室模型与任意循环模型的耦合仿真算法n由压力反射效应调节的心血管数学模型Hardware-in-the-loop-simulation of the cardiovascular system, with assist device testing applicationB.M. Hanson et al. J ELSEVIER, Medical Engineering & Physics 29 (2007) 367374nThe paper presents a technique for

4、evaluating the performance of a cardiac assist device prior to in vivo trials by combining physical (mechanical) testing with a numerical, computerised model of a biological system.nThis Hardware-in-the-loop simulation combines a realistic numerical model of the heart and cardiovascular system with

5、a controllable physical heart simulator.Numerical model of cardiovascular systemHeart SimulatornApplying mechanical assistance in the form of direct cardiac compression can increase blood pressure and cardiac output from a weakened heart.nCompared to testing on an animal model, it is possible to per

6、form repeated experiments, all on an identical patient model, in a short space of time, in a non-clinical setting. nCompared with a purely numerical simulation, HIL simulation enabled evaluation of the effect of the real, physical performance of the prototype assist device.Simulation Algorithm for t

7、he Coupling of the Left Ventricular Mechanical Model with Arbitrary Circulation ModelYutaka NOBUAKI et al. Engineering in Medicine and Biology 27th Annual Conference2005, 7632-7635 Cardiovascular dynamics is the result of the nonlinear interactions between the left ventricular mechanical model and t

8、he circulation model, simultaneous calculation of both models by a strong coupling method is necessary to obtain an accurate simulation result.Left Ventricular ModelLV ModelTime-varying Elastance ModelLV Mechanical ModelAdvantage: Easy to realizeDisadvantage: Difficult to incorporate the characteris

9、tics of the ventricular cells and the structure of the LVEasy to incorporate various physiological properties such as myocardial cell orientation,excitation conducting system, mechanical properties, myocardial electrophysiological model and so on.Therefore, it is very effective to use LV mechanical

10、model to analyze various aspects of the cardiovascular dynamics.Left ventricular mechanical modelH : function for calculating the transformationVlv: left ventricular volume.Plv：inner pressure of LVFb： cell contraction forceCirculation ModelCirculation ModelTwo compartment Windkessel modelTwo element

11、 Windkessel modelFinite Element MethodA cardiovascular dynamics simulation system is constructed by a general finite element method solver as a simulator of the left ventricular mechanical model and an existing software as a simulator of the circulation model. Since most of the circulation models ar

12、e expressed by the equation similar to either of these two models, the proposed coupling algorithm is generally applicable, and the model can be easily exchanged.A Mathematic Model of a Cardiovascular System Regulated by the BaroreflexShaohui Chen et al. Proceedings of the 2006 American Control Conference 701-706A dynamic, nonlinear, lumped parameter model of the cardiovascular system coupled with a baroreflex model is presented. The baroreflex is an important internal feedback mechanism in the body whose function i