冠状动脉粥样硬化性心脏病患者特征性的心磁图表现

The diagnostic value of Magnetocardiography for patients with coronary artery disease

目的：观察冠状动脉粥样硬化性心脏病（冠心病）患者的特征性心磁图表现,并进一步筛选有诊断价值的心磁图参数。方法：采用心磁图仪,对122例冠心病患者及108例对照者心磁图电流密度图的平均分级、异常磁图百分比、复合心室激动指数（complex ventricular excitation index,CVEI）、R波与T波的最大磁场值比值（R-max/T-max比值）、T波起始处电流密度最大电轴方向（Tbegin）、T波顶点处电流密度最大电轴方向（Tapex）参数进行分析,比较2组间的心磁图差异。结果：正常对照组心磁图在ST-T整个复极过程中存在双极对称结构,只有一个主要电流方向,指向左下0°~90°,Tbegin在10°~25°之间,T-max在25°~35°之间;异常磁图百分比、平均分级、复合心室激动指数及R-max/T-max比值分别在9.10%~25.75%、2.10~2.50、-12.75~64.00和2.53~4.65之间。冠心病组患者的心磁图则明显存在电流密度的异质性特点,并缺乏双极对称结构。与对照组相比,冠心病组的平均分级、异常磁图百分比、R-max/T-max比值、Tbegin和Tapex值均明显大于对照组（分别为2.91比2.36,66.82%比18.24%,5.52比4.02,84.59比25.17,62.97比32.75,P均〈0.01）,而冠心病组的复合心室激动指数值则显著低于对照组（-37.10比20.93,P〈0.01）。结论：冠心病组与对照组相比,心磁图存在明显异常。作为一种新的无创性检测心肌缺血的有效手段,心磁图对于冠心病的诊断具有一定价值。

Objective： To study the characreristic presentation of magnetocardiography （MCG） in patients with coro- nary artery disease （CAD） for screening the useful diagnostic parameters. Methods： One hundred and twenty-two CAD patients were enrolled, and 102 healthy subjects were served as controls. MCG mapping was performed by MCG-7 （MaG- IC, Magsean GmbH） installed in an unshielded environment. Several parameters were used for detail analysis, including ACTM （average classification of total maps）, RAM （ratio of abnormal maps）, CVEI（complex ventricuiar excitation index）, R-max/T-max （ratio of the maximum magnetic value between R and T wave）, Tbegin（the angle of main current direction at the offset of T wave）, Tapex （the angle of main current direction at the apex of T wave）. MCG parameters between the CAD group and the control group were compared. Results： The current density map of normal people showed two-dipole structure during the whole ST-T reporlarization period, the maximal vectors were directed to left-downwards （sector from 0°to 90°） during the whole ST-T reporlarization period. Tbegin laid in 10°-25°, T-max laid in 25°-35°; RAM, ACTM, CVEI and R-max/T-max ratio were in the range of 9.10% -25.75%, 2.10-2.50,-12.75 -64.00 and 2.53-4.65, respective- ly. Current density maps in CAD group showed inhomogeneous distribution without dipole structure. ACTM, RAM, R-max/ T-max, Tbegin and Tapex in CAD group were higher than those in control group （2.91 vs 2.36, 66.82% vs 18.24%, 5.52 vs 4.02 , 84.59 vs 25.17 and 62.97 vs 32.75, P〈0.01）. CVEI in CAD group was lower than that of control group（-37.10 vs 20.93, P〈0.01）. Conclusions： MCG differs significantly between CAD patients and healthy subjects. As a non-invasive and non-radioactive method, MCG is an useful approach for diagnosing CAD.