全心房心外膜标测显示系统及其三维等电位图插值方法的研究

【作者】 陆唯佳；

【导师】 方祖祥；

【作者基本信息】 复旦大学 ， 生物医学工程， 2009， 博士

【摘要】 本文介绍了一款能够实时记录心外膜电活动的128道全心房心外膜标测系统。为了形象的表征电活动在心外膜表东的传递，帮助理解复杂心律失常的形成、维持机制。该标测系统采用了等电位图的出图方式。等电位图是种常见的标测序列图表征方式，它将标测的电信号幅度直接在心脏的三维几何模型上用伪彩色绘制出来，相同电压区域用同一种颜色标识。绘制等电位图需要得到心脏三维几何模型上每个位置的电压，所以对非电极所处位置的电压推算需要一个快速、有效的插值算法。该插值算法依据有限个标测记录位点上的信号，插补得到心脏三维几何模型上各个位置的电压。在本文的第三章介绍了该系统中使用的三维插值算法，这一方法能在12us内完成整个几何模型的插值(6134个插值单元)、面且和常见的B样条插值相比，在8条测试样本组成的测试集上，两个测试电极上的归一化后的平均均方误差(RE)的均值分别减少18．25％和16．35％。但是由于其本质是种线性插值，所以会引入误差。比如在除极波前的区域和除极波刚经过的区域，心外膜电场应该是非线性的，但是当插值参考点跨越这两个区域的时候，应用该插值方法得到的结果却是线性的(详见3．5节的论述)。在本文的后半部分，本文作者着力于改进这种插值算法，尽量减少插值引入的误差。用心外膜标测研究房颤等多激动源、多传播途径、时变的复杂心律失常是日前的研究热点。因为其标测电极紧靠着心外膜表面，标测精度高，有空间位置与电激动位置符合的特点，而且可以进行活体标测。常规的电生理检测手段效果往往不尽如人意，因为有的空间标测精度不高、有的标测周期过长、有的不能进行活体标测。在本文的最后，介绍了几次和北京安贞医院，上海中山医院合作进行的动物实验。用实测的动物数据制作的三维等电位图来进行房颤的电生理研究，并且得出与前人论文相同的结论，从而进一步验证了系统的效能。更多还原

【Abstract】 A novel whole-atria epicardial mapping system is proposed in this study,which can generate the isopotential map to help understanding the generation aswell as the maintenance of the atrial fibrillation (AF).The isopotential map isthe most straightforward presentation to use contours or constant colors paintingthe region with same potential.Of great practical concern in isopotentialmapping is the trade-off between spatial sampling density and the coverage ofcardiac geometrical model,the limits of which are defined by the finite numberof channels that can be sampled synchronously.A proper interpolation can solvethis problem and get the potential distribution on the whole geometrical model.In the third chapter,such a 3D interpolation method is proposed,which canfinish one interpolating routine on the whole geometrical model (6134 triangles)in 12us.The relative error (RE)of this method on 2 test electrodes isrespectively 18.25% and 16.35% smaller than the B-Spline interpolation.Butthis method has some subtle ambiguities and limitations because it is a linearone.For example,it may cause considerable distortion during activation,whenthere is a strongly non-linear distribution of potential with space across thewavefront.In the latter part of this study,some additional proceedings aredesigned for constraining this kind of distortion.Such a kind of epicardial mapping system is becoming more and morepopular in studying the complex arrhythmias which usually have multiplesources,multiple propagation paths and are time varying.Because the electrodeused in the system is sutured tightly on the epicardial surface,and the voltagevariation on the electrode pads can synchronously reflect the propagation ofexcitation.In the other hand,the regular electrophysiological examinationmethod,such as ECG,torso mapping and etc,are not appropriate for complexarrhythmias studying.Because some of them have not enough spatial resolution,others take too much time to collect useful information to generate a map,or are not suitable for in-vivo mapping.In the last chapter,we bring forward someanimal experiments carried out in Anzheng Hospital,Beijing and ZhongshanHospital,Shanghai.In one of these experiments,the epicardial mapping systemis used in the studying ofvagal AF by using the Scherlag’s experiment protocol,which is constantly stimulating on the IVC-LA fat pad located between theinferior vena cava and the inferior surface of the left atrium.In this experiment,several onsets of AF are observed.The isopential mapping of these AFsindicates the same conclusion described by Scherlag,which is theelectrophysiological characteristics of myocardium might have been changedduring the sustaining of vagal AF.This experiment can prove the feasibility ofour epicardial mapping system.更多还原