心磁图对老年冠心病的诊断价值

目的探讨心磁图(magnetocardiography,MCG)对冠心病的诊断价值。方法应用德国SQUID7通道非屏蔽心磁图仪,对90例60岁以上[冠状动脉(冠脉)病变≥70%患者46例,冠脉病变<50%者44例]冠心病患者进行MCG的检测。选择心脏复极过程,以每12ms为间隔作出ST-T间期的电流密度分布图,以每幅图分级的平均数(averageclassification of total maps,ACTM)、异常电流分布图占所有电流密度分布图的比率(ratio of abnormal maps,RAM)、每幅图异常电流所分布的部位这3个指标作为判断标准。结果(1)冠脉病变≥70%和冠脉病变<50%的患者,心肌复极期(ST-T段)中ACTM、RAM差异均具有显著性意义。(2)在方法学上应用受试者工作特征曲线(ROC曲线)分析并结合临床,ACTM的敏感性为87%,特异性为59.1%。RAM的敏感性为84.8%,特异性为61.4%。结论MCG是一种无创性的、敏感性较高的筛选诊断冠心病的新方法。

The clinical value of magnetocardiography in diagnosis of coronary heart diseases

Objective To evaluate the clinical value of magnetocardiography(MCG) in the diagnosis of coronary heart disease(CHD).Methods Ninety patients aged≥60 years were included in this study.Of them 46 had angiographically documented CAD(coronary artery stenosis ≥70%) and normal ventricular function and 44 were controls(coronary artery stenosis <50%).A standard 12-lead ECG was obtained in all subjects.The MCG recordings were taken from 36 positions under resting conditions by means of 7-channel SQUID(super conducting quantum interference device) magnetometer in an unshielded location.From these,current density vector maps were generated during the ST-T interval.Each map was then classified using a classification system with a scale from 0(normal) to 4(grossly abnormal).The maps of magnetic field distribution were plotted in course of ST-T interval with 12 ms steps on the bases of two-dimensional interpolation algorithms.Two quantitative indicators were analyzed:average classification of total maps(ACTM),ratio of abnormal maps(RAM).Results ACTM and RAM were higher in CAD than in control(ACTM 3.04±0.64 vs 2.72±0.82,P=(0.043),RAM 65.28±31.50 vs 50.84±36.26,P=0.047).The classification of the current maps was lower in control(category 0,1 or 2) than in CAD(category 3,4),P<0.05.Conclusion MCG might be a new noninvasive screening method for diagnosis of coronary artery diseases.