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ID 111502
著者
Ikefuji, Hiroyuki JA Kochi Hospital
野村, 昌弘 The University of Tokushima
Mori, Toshifumi The University of Tokushima
Kondo, Noriyasu The University of Tokushima
Ieishi, Kiyoshi The University of Tokushima
Fujimoto, Sayuri The University of Tokushima
キーワード
magnetocardiography
current density map
cardiac current
資料タイプ
学術雑誌論文
抄録
A close relationship exists between electric current and the magnetic field. However, electricity and magnetism have different physical characteristics, and magnetocardiography (MCG) may provide information on cardiac current that is difficult to obtain by electrocardiography (ECG). In the present study, 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.
The 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.
The findings herein suggest that opposing dipoles of the ventricular depolarization and repolarization vectors were summed and evaluated as a single dipole in the electrocardiogram. However, MCG facilitated the detection of multiple dipoles because of its superior spatial resolution as well as difference in physical properties between magnetic and electrical fields. Our results suggest that MCG with a current density map is useful for detecting cardiac current undetectable by ECG in an early stage.
掲載誌名
The Journal of Medical Investigation
ISSN
13496867
13431420
cat書誌ID
AA11166929
AA12022913
出版者
Faculty of Medicine Tokushima University
54
1-2
開始ページ
116
終了ページ
123
並び順
116
発行日
2007-02
EDB ID
出版社版DOI
出版社版URL
フルテキストファイル
言語
eng
著者版フラグ
出版社版
部局
医学系