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Cardiac electrical activity imaging of patients with CRBBB or CLBBB in magnetocardiography 下载免费PDF全文
A new method for the imaging of cardiac electrical activity in patients with complete right bundle branch block (CRBBB) or complete left bundle branch block (CLBBB) is investigated using magnetocardiographic recordings of the surface of the body. This is based on the assumption that an equivalent single-current dipole moves along the unblocked bundle branch, whose position in the measurement plane is expressed in terms of the maximum and minimum, as well as the maximum gradient value of the measured magnetic field. The trajectory of the moving dipole on the measurement plane is indicative of theexcitation conduction of the CRBBB or CLBBB subject during ventricular depolarization and repolarization, which is deduced by comparing each change between the dipole moment and the maximum current density in a corresponding pseudo-current density map. In summary, this method can distinguish CRBBB from CLBBB subjects by means of the dipole depth and two dipole moment components. The possibility of visualizing the excitation conduction in a CRBBB or CLBBB subject during ventricular depolarization and repolarization is then discussed. 相似文献
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利用核磁共振图像(MRI)中提取的人体和心脏边界,根据边界元方法(BEM)建立了一个考虑左、右心房和心室的多腔体心脏磁场模型.分析了用该模型得到的36通道心脏磁场数据和特定时刻的磁场图.并在此基础上,研究了完全性右束支传导阻滞(CRBBB)和完全性左束支传导阻滞(CLBBB)病人ST-T段的心脏电活动.结果显示,用移动单电流偶极子模拟的单束支电兴奋传导所产生的磁场图与用超导量子干涉器(SQUID)测量的CRBBB/CLBBB病人数据绘制的心脏复极时的心磁图(MCG)十分相似.结果表明,该多腔体心脏BEM模型可用于CLBBB/CRBBB病人心脏磁场逆问题的研究.此外,文中给出了两个评价指标:测量平面上多腔体与单腔体的心脏磁场强度极大值之比,以及两种模型的36个测量点上磁场强度均方根之比.分析表明,多腔体心脏模型更贴近人体心脏的实际情况.该模型中心脏组织电导率参数的取值,以及等效电流偶极子的位置和个数决定了磁场的强度和分布. 相似文献
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