Early diagnosis of myocardial ischemia using magnetocardiogram

我们研究了电流密度图方法（通过磁梯度估计心脏电流）是否有助于心电图无法检测到的心脏电流的可视化。1)梗死向量的评估使用心磁仪记录老年下壁心肌梗死（MI组）和正常健康受试者（normal组）。心脏的电动势由电流密度图估计。在心室去极化期电流密度图中，心肌梗死组与正常人不同，从心室去极化期的心磁图中推导出多个电流密度。在心肌梗死组的4例患者中，提示存在多个体表心电图未检测到的电流源。心磁图能够检测梗塞的电动势，这是不能从心电图数据推断出来的。研究对象为健康成人50例（N组）、左心室负荷过重患者40例（LVO组）、右心室负荷过重患者15例（RVO组）、陈旧性下壁心肌梗死患者10例（OMI组）、糖尿病患者30例（DM组）。用液氦二阶导数超导量子干涉装置（SQUID）梯度仪记录了mcg。分别制备单极心前导联和mcg的等电位图和电流密度图，并检测心脏电流。脑室去极化期电流密度图显示N组有一个电流密度峰。而在OMI组中，电流密度图显示出多个电流密度区域的峰值。在RVO组中，在右上区和左胸区检测到两个电流密度峰，这两个偶极子分别来自右心室和左心室源性心脏电流。此外，右心室电流密度的大小与肺动脉收缩压之间存在显著的相关性。N组心室复极期电流密度图显示只有单一电流源。然而，即使在LVO、DM和OMI组等电位图上没有异常的患者中，电流密度图上也经常发现异常的电流源。我们的研究结果表明，MCG与电流密度图在早期检测ECG无法检测到的心脏电流是有用的。少

We investigated the issue of whether the current density map method, in which cardiac current is estimated from the magnetic gradient, facilitates the visualization of cardiac current undetectable by ECG.1) Evaluation of an infarction vectorOld inferior myocardial infarctions (MI group) and normal healthy subjects (Normal group) were recorded using magnetocardiometer. The electromotive force of the heart was estimated from a current density map. In the current density map of the ventricular depolarization phase, multiple current densities were deduced from magnetocardiograms of the ventricular depolarization phase in the MI group, unlike normal subjects. In 4 patients in the MI group, multiple current sources were suggested, which were not detected in a body surface electrocardiogram. Magnetocardiogram is capable of permitting infarct electromotive forces to be detected, which could not be deduced from electrocardiography data.2) Detection of cardiac current undetectable by electrocard … More iography using magnetocardiography in various cardiac diseasesThe subjects were 50 healthy adults (N group), 40 patients with left ventricular overloading (LVO group), 15 patients with right ventricular overloading (RVO group), 10 patients with an old inferior myocardial infarction (OMI group), and 30 patients with diabetes mellitus (DM group). MCGs were recorded with a second derivative superconducting quantum interference device (SQUID) gradiometer using liquid helium. Isopotential maps and current density maps from unipolar precordial ECG leads and MCGs, respectively, were prepared, and the cardiac electric current was examined. The current density map at the ventricular depolarization phase showed one peak of current density in the N group. However, in the OMI group, the current density map showed multiple peaks of current density areas. In the RVO group, two peaks of current densities were detected at the right superior region and left thoracic region and these two diploles appeared to be from the right and left ventricular derived cardiac currents, respectively. Moreover, there was a significant correlation between the magnitude of the current density from the right ventricle and the systolic pulmonary arterial pressure. The current density map at the ventricular repolarization phase in the N group showed only a single current source. However, abnormal current sources in the current density maps were frequently detected even in patients showing no abnormalities on isopotential maps in the LVO, DM, and OMI groups.Our results suggest that MCG with a current density map is useful for detecting cardiac current undetectable by ECG in an early stage. Less