Electrical & Computer Engineering, Department of


Date of this Version



Published in IRE Transactions on Bio-Medical Electronics 10:4 (Oct. 1963), pp. 145-149; doi 10.1109/TBMEL.1963.4322823 Used by permission.


Experiments have been conducted which reveal the existence of a detectable magnetic field associated with cardiac electrical activity. The relationship between the magnetic record and the electrocardiogram has been explored and it is shown that under certain conditions of axis orientation the voltage induced into a toroidal sensing element around the heart has the form of the first time derivative of the electrocardiogram. A formula based on Maxwell's equations has been developed to relate these two phenomona.