Stroink G, Lant J, Elliott P, Charlebois P, Gardner M J
Department of Physics, Dalhousie University, Halifax, Nova Scotia, Canada.
J Electrocardiol. 1992 Apr;25(2):129-42. doi: 10.1016/0022-0736(92)90117-i.
Magnetocardiograms were recorded from 30 normal (N) subjects, 15 myocardial infarct (MI) patients, and 15 ventricular tachycardia (VT) patients. Discrimination between the groups was affected by iso-integral magnetic field mapping (MFM) and trajectory plotting of MFM extrema. Iso-integral MFM for the QRST, QRS, and ST-T intervals was created for each test group member. A polarity score, based on the number of extrema features present, was assigned to each iso-integral MFM. Differences in group mean integral of QRST map polarity scores were significant (p less than 0.05) between MI and N, between VT and N (p less than 0.005), and between MI and VT (p less than 0.05) subjects. integral of ST-T map polarity scores were significantly (p less than 0.0001) different between VT and N and between MI and VT (p less than 0.001) subjects. Discrimination between MI and VT patients, based on polarity score difference, was 56% accurate using integral of QRS maps and 73% accurate using integral of ST-T maps. For each subject, time-normalized MFM was used to construct trajectory plots of the maxima and minima in the QRS and ST-T intervals. Discrimination between MI and VT patients was based upon intergroup differences in fragmented trajectory plots. When the number of discrete trajectories and/or the total number (F) of trajectory points at which discrete trajectories coexist were considered, QRSmin trajectory plots were significantly (p less than 0.05) different for VT and N, but not for MI and N subjects. The significant (p less than 0.05) difference between MI and VT trajectory plots enabled 76% accuracy for MI and VT identification. ST-Tmax trajectory plots show significantly (p less than 0.0001) higher F values for VT patients facilitating accurate (87%) discrimination between MI and VT patients. These results suggest that the abnormalities of repolarization processes, displayed by MFM as multipolar integral of ST-T maps and/or as fragmented trajectory plots of ST-T extrema, may be useful indicators of the arrhythmia substrate/processes that characterize VT and vulnerable MI patients.
记录了30名正常（N）受试者、15名心肌梗死（MI）患者和15名室性心动过速（VT）患者的磁心动图。通过等积分磁场映射（MFM）和MFM极值的轨迹绘制来区分不同组。为每个测试组成员创建了QRST、QRS和ST - T间期的等积分MFM。根据存在的极值特征数量为每个等积分MFM分配一个极性分数。MI组与N组之间、VT组与N组之间（p < 0.005）以及MI组与VT组之间（p < 0.05），QRST图极性分数的组平均积分差异具有统计学意义。VT组与N组之间以及MI组与VT组之间（p < 0.001），ST - T图极性分数的积分差异具有高度统计学意义（p < 0.0001）。基于极性分数差异，区分MI患者和VT患者时，使用QRS图积分的准确率为56%，使用ST - T图积分的准确率为73%。对于每个受试者，使用时间归一化的MFM构建QRS和ST - T间期最大值和最小值的轨迹图。基于碎片化轨迹图的组间差异来区分MI患者和VT患者。当考虑离散轨迹的数量和/或离散轨迹共存的轨迹点总数（F）时，VT组与N组的QRSmin轨迹图存在显著差异（p < 0.05），但MI组与N组的QRSmin轨迹图无显著差异。MI组与VT组轨迹图之间的显著差异（p < 0.05）使得MI和VT识别的准确率达到76%。ST - Tmax轨迹图显示VT患者的F值显著更高（p < 0.0001），有助于准确区分MI患者和VT患者（准确率87%）。这些结果表明，MFM显示为ST - T图的多极积分和/或ST - T极值的碎片化轨迹图所呈现的复极化过程异常，可能是表征VT和易患MI患者的心律失常基质/过程的有用指标。
