Nousiainen J J, Lekkala J O, Malmivuo J A
J Electrocardiol. 1986 Jul;19(3):275-90. doi: 10.1016/s0022-0736(86)80037-1.
The normal vector magnetocardiogram and its statistical variation are described in detail. The magnetic heart vector of 18 healthy subjects is detected with the corrected unipositional lead system and analysed together with the simultaneously recorded Frank vector electrocardiogram. The mean values and standard errors for the magnitudes and directions of the magnetic QRS and T waves are calculated with a digital computer. The interindividual variability of the normal magnetic and electric heart vectors was found to be about the same. The inaccuracy in the detector placement at the fourth intercostal space gives rise to only a small error in the direction of the detected magnetic heart vector. This is due to the self-centering effect of the lead fields in the heart's region, which arises from the difference in conductivity between the well-conducting heart and the intracardiac blood mass and the low-conducting lungs. The shape of the magnetic heart vector remains unchanged when it is measured at various distances from the chest surface on the line which is perpendicular to the frontal plane and joins with the beginning of the fourth intercostal space. The relationship between the normal magnetic and electrical heart vectors was also studied. The angle between the maximum magnetic and electrical heart vectors was shown to differ slightly from the theoretically predicted value of 90 degrees. Our results support the theoretically known difference in the relative sensitivities of the magnetocardiographic and electrocardiographic leads: the magnetic heart vector is more sensitive than the electrical vector to the terminal phase of the ventricular depolarization, when the activation in the heart appears in a more tangential direction than at the initial phase.
详细描述了正常向量心磁图及其统计变化。使用校正后的单位置导联系统检测了18名健康受试者的磁心向量，并与同时记录的Frank向量心电图一起进行分析。用数字计算机计算磁QRS波和T波的大小和方向的平均值及标准误差。发现正常磁心向量和电心向量的个体间变异性大致相同。探测器放置在第四肋间空间时的不准确仅会在检测到的磁心向量方向上产生小误差。这是由于心脏区域导联场的自定心效应，其源于良导电的心脏与心内血团之间以及低导电的肺之间的电导率差异。当在垂直于额面并与第四肋间空间起点相连的线上距胸壁表面不同距离处测量时，磁心向量的形状保持不变。还研究了正常磁心向量与电心向量之间的关系。最大磁心向量与电心向量之间的夹角显示略不同于理论预测值90度。我们的结果支持心磁图和心电图导联相对灵敏度在理论上已知的差异：当心脏中的激活以比初始阶段更切向的方向出现时，磁心向量比电向量对心室去极化的末期更敏感。
