Impedance magnetocardiogram.
We have developed an impedance magnetocardiogram (IMCG) system to detect the change of magnetic field corresponding to changes in blood volume in the heart. A low magnetic field from the electrical activity of the human heart--the so-called magnetocardiogram (MCG)--can be simultaneously detected by using this system. Because the mechanical and electrical functions in the heart can be monitored by non-invasive and non-contact measurements, it is easy to observe the cardiovascular functions from an accurate sensor position. This system uses a technique to demodulate induced current in a subject. A flux-locked circuit of a superconducting quantum interference device has a wide frequency range (above 1 MHz) because a constant current (40 kHz) is fed through the subject. It is shown for the first time that the system could measure IMCG signals at the same time as MCG signals.
Central Research Laboratory, Hitachi, Ltd, Kokubunji, Tokyo, Japan. kandori@crl.hitachi.co.jp
A
A
Kandori
T
T
Miyashita
D
D
Suzuki
K
K
Yokosawa
K
K
Tsukada
D000328:Adult; D055592:Biophysical Phenomena; D001703:Biophysics; D002307:Cardiography, Impedance / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008280:Magnetics / Q000295:instrumentation; D008297:Male