多部位心电标测精品医学PPT课件

多部位心电标测 （Electrocardial potential mapping） 南开大学物理学院 生物物理系 李川勇 主要内容 心电信息学 What is ECG（心电图）? Multi-channel ECG recording system， ECG potential mapping， ECG simulation (forward & inverse ECG) Its applications Future development 心电信息学 In a general term, it refers to the informatics of electrical activity of heart. 心电信息学是把通过各种手段所获得的有关心脏电活动的信息，加以处理和分析，总结出能示心脏电生理状态的特征量或参数；从而达到对心脏的认识。 原始信号的获得， 对原始信号的处理， 一、What is ECG (electrocardiograph)? 在整个心脏电激动的综合过程, 心肌细胞兴奋的产生、传导和恢复过程中产生生物电变化，用仪器在人体表面的这种电位变化波形叫心电图, 1905年Einthoven发明了心电图机记录心电图，临床上有单道心电图机、三道心电图机、同步12导心电图机等； 心电图学主要研究心电图的产生原理；分析心电图的图形以了解心脏活动的情况，协助诊断心脏疾病（如心律失常等）并研究其发生机理。 近年来心电图学在理论和实践方面都有很大进展，心电图诊断已成为临床医学特别是心脏内外学科的一个重要课。 magnetocardiography (心磁图) 心室肌细胞动作电位 0：除极(1-2ms)； 1：复极初期 (10ms)， 2：缓慢复极相（平台期）(100-150ms) ， 3：快速复极晚期(100-150ms) ， 4：静息期 心脏传导系统 窦房结: 心脏的起搏兴奋点, 其细胞自发产生50-100次/分的可传导AP, 心房的传导: 心房传导束-->右心房-->左心房 传导系统的传播: 房室束-->希氏束(His bundle)-->左、右分支-->普金野（Purkinje）纤维网->心室肌, 电兴奋通过Purkinje网使心室肌细胞兴奋， Measurement of ECG 肢体导联 ECG recording machine Basic features of ECG 二、Why mapping? 传统12导联的电极位置的局限性； 80年代提出，指采用多个电极（24-250）均匀排列覆盖整个躯干，记录多部位的体表心电信息，以获得心电信号更多的空间信息。 记录系统：由计算机控制的多通道数据采集系统，完成心电信号的采集、显示、处理。 mapping system 无创检测, 体表心电图: 标准12导联，动态心电图，体表多部位检测(body surface potential mapping， BSPM)， 体表心磁图（Magnetocardiography，MCG）， 有创检测, 动作电位、单向动作电位的测量， 心内膜、心外膜心电图（Endocardial and epicardial electrogram）， 希氏束电图（His-Bundle electrogram） 2-1、An example 256 channel system 心电信号标准图， Its features 256 channels Battery powered Three functions: ECG, EGG, late potential Programmable microcontroller 12-bit, 800ns ADC Programmable channel amplification 50,100,200,500,1k,2k,5k,10k Programmable sampling rate 2, 10,20,100,200,500,1k,2k (Hz) 2-2、192-channel system 2-3、256 channel system ActiveTwo system by BioSemi. 256 channel AD-box with battery 三、Electrocardial potential mapping Body surface potential mapping (BSPM) 体表电位标测 Epicardial potential mapping 心外膜电位标测 Endocardial potential mapping 心内膜电位标测 Three-dimensional potential mapping 三维电位标测 3-1. Body surface mapping 图： Electrodes Panel 4x12 : Total of 48 electrodes on 1 connector Mapping in color Mapping in different times 3-2. Epicardial potential mapping Electrodes: electrode sock Epicardial mapping 60s after LAD Occlusion Coronary artery 120s after LAD Occlusion LAD：左前降支；LCX：左回旋支； RCA：右旋支 3-3. Endocardial potential mapping Cardiac catheter (心导管) for patient, Umbrella electrode for animal experiment; 3-4 Three dimensional mapping Endocardial, epicardial and body surface recording at the same time. With needle electrodes, transmural information can be obtained. 常规心电图描述的是窦性心律， 人的固有心率（100-120bpm）受到迷走神经和交感神经的共同作用，前者使之减慢，后者使之加快。 四、 ECG simulation Current source Volume conductor Governing equation Numerical solution Experimental validation ECG problems source of electrical current at the surface of the heart : ΓE propagation through the chest, bioelectric volume conductor : Ω measure of potential at the surface of the torso : ΓT Φ is the electrostatic potential, σ is the electrical conductivity tensor, Here a boundary surface around the region which includes the sources is defined and the source is recasted that surface. Two models Forward model Well-posed problem Inverse model Ill-posed problem （病态问题） Well-posed problem meets the three criteria: 1 - for each set of data, there always exists a solution; 2 - the solution is unique; 3 - the solution depends continuously on the data. However, the bioelectric inverse problem lacks two criteria: 1) it is not a unique solution; 2) The solution does not depend continuously on the data. Ill-posed （不适定的，病态的） ECG inverse problem To obtain quantitative information about cardiac activity， the inverse problem of electrocardiography must be solved. The ECG inverse approaches are used to non-invasively reconstruct the electrical state of the heart from remote recordings of the electrical activity at the body surface. There are many algorithms available to solve the inverse problems. These algorithms must be experimentally validated. 五、The applications Methodology of modern BSPM includes: computerised signal collection (计算机化的信号采集) (simultaneous multichannel recording from several decades of leadpoints on the chest surface, digitalisation of ECG signal, multiplexing and storage), computerised data presentation (计算机化的数据表示) (ECG curves, different templates of maps as a result of application of mathematical interpolations techniques like linear or polynomic, data compression e.g. time integration of the voltage, rapid calculation of quantities not directly measured like different durations, angles etc.) computerised data evaluation (计算机化的数据分析) (signal processing based on medical knowledge). ECG Data evaluation Time series analysis（时间序列分析）, HRV (heart rate variability) Spatial analysis （空间分析） QT dispersion, Inverse ECG, source prediction Spatial pattern of ECG parameters Spatial-temporal analysis （时空分析） Cardiac activation time 心率变异（HRV） HRV是指心率的波动，或者心动周期之间的差异性。 正常人的心率有相当于平均值10%的波动，这种波动程度的降低是心脏异常的表现。 HRV的分析方法： 时域分析，RR间期的标准差，<50ms异常 频域分析，LF(0.04-0.15Hz)和HF(0.15-0.4Hz)的功率谱的比较， 非线性分析：散点图，相关维数，复杂度等。 常规心电图描述的是窦性心律， 人的固有心率（100-120bpm）受到迷走神经和交感神经的共同作用，前者使之减慢，后者使之加快。 Dispersion in ventricular repolarisation (心室复极不一致) 研究表明：室性心律失常是由心室复极不一致导致的，进而研究QT离散度等， 通过分析ST段位移的空间分布确定心肌缺血部位等； 分析体表、心脏表面的兴奋时间图，判断异常心肌的部位等； 国内的研究状况 浙江大学生命科学与医学学系； 天津大学精仪学院生物医学工程与科学仪器系； 重庆大学电气工程学院； 第四军医大学生理教研室； 首都医科大学 国外研究状况 北美一些大学，Duke University, University of Utah，Case Western Reserve University，Dalhousie University (Canada) 欧洲，University of Amsterdam，University of Ulster (UK), university of Oxford, 日本，University of Tokyo, Yamagata University School of Medicine，National Cardiovascular Center， Australia, New Zealand Future development Low-cost, easy-to-use recording system Electronic engineer Computer scientist Physicist Computer simulation on ECG Physicist Mathematician Effective diagnosis software Medical doctor Software engineer 参考文献 http://www.biosemi.com/index.htm http://medlib.med.utah.edu/kw/ecg/index.html http://butler.cc.tut.fi/~malmivuo/bem/bembook/ magnetocardiography (心磁图) 0：除极(1-2ms)； 1：复极初期 (10ms)， 2：缓慢复极相（平台期）(100-150ms) ， 3：快速复极晚期(100-150ms) ， 4：静息期 窦房结: 心脏的起搏兴奋点, 其细胞自发产生50-100次/分的可传导AP, 心房的传导: 心房传导束-->右心房-->左心房 传导系统的传播: 房室束-->希氏束(His bundle)-->左、右分支-->普金野（Purkinje）纤维网->心室肌, 电兴奋通过Purkinje网使心室肌细胞兴奋， 心电信号标准图， 图： LAD：左前降支；LCX：左回旋支； RCA：右旋支 常规心电图描述的是窦性心律， 人的固有心率（100-120bpm）受到迷走神经和交感神经的共同作用，前者使之减慢，后者使之加快。 Here a boundary surface around the region which includes the sources is defined and the source is recasted that surface. Well-posed problem meets the three criteria: 1 - for each set of data, there always exists a solution; 2 - the solution is unique; 3 - the solution depends continuously on the data. However, the bioelectric inverse problem lacks two criteria: 1) it is not a unique solution; 2) The solution does not depend continuously on the data. Ill-posed （不适定的，病态的） 常规心电图描述的是窦性心律， 人的固有心率（100-120bpm）受到迷走神经和交感神经的共同作用，前者使之减慢，后者使之加快。