Magnetic Fields around the Torso: Production by Electrical Activity of the Human Heart

Abstract

A search was made outside the torso for fluctuating magnetic fields produced by the heart. Detector and subject were housed in a highly shielded enclosure. Magnetic signals with amplitudes of 10^-8 to 10^-7 gauss were detected synchronously with the electrocardiogram, confirming previous reports. A magnetocardiographic chest map, consisting of the magnetic field plotted against time at various spatial positions, shows genteral QRS and T-wave structure, as in the electrocardiogram; this structure varies with spatial position.