Uchikawa Y, Kim B S, Kobayashi K
School of Science and Engineering, Tokyo Denki University, Saitama, Japan.
Neurol Clin Neurophysiol. 2004 Nov 30;2004:92.
We carried out a three-dimensional (3-D) vector measurement of exercise-induced magnetocardiograms (MCGs) for normal subjects with a wooden and brass-based bicycle ergometer. MCGs were measured by a 3-D second-order gradiometer connected to 39-channel SQUIDs, which can detect magnetic field components perpendicular to the chest wall (Bz) and tangential to the chest wall (Bx, By) simultaneously. Time-frequency analysis was applied to rest times and exercise-induced MCG data. It was shown that the power spectrum of the ST segment was different between the rest times and exercise-induced MCG. Principal component analysis (PCA) was also applied to the result of time-frequency analysis and the time course of frequency for the ST segment was evaluated quantitatively. It found that dominant frequency of the ST segment in the rest time was ranged 5.5 to 6.5 Hz in all components. And it was clearly shown that the peak frequency of the exercise-induced MCG was shifted to 10.5 Hz compared to that of rest MCG.
我们使用基于木质和黄铜的自行车测力计，对正常受试者运动诱发的心磁图（MCG）进行了三维（3-D）矢量测量。MCG由连接到39通道超导量子干涉仪的三维二阶梯度仪测量，该梯度仪可同时检测垂直于胸壁的磁场分量（Bz）和平行于胸壁的磁场分量（Bx、By）。对静息期和运动诱发的MCG数据进行了时频分析。结果表明，静息期和运动诱发的MCG的ST段功率谱不同。主成分分析（PCA）也应用于时频分析结果，并对ST段的频率随时间变化过程进行了定量评估。结果发现，静息期所有分量中ST段的主导频率范围为5.5至6.5赫兹。并且清楚地表明，与静息MCG相比，运动诱发的MCG的峰值频率移至10.5赫兹。
