The normal human magnetocardiogram. II. A multipole analysis.

This paper presents a multipole analysis of the QRS complex of the normal magnetocardiogram (MCG) of six normal subjects. The multipole strengths up to the octupole term were determined from the measured distribution of the z-component of the cardiac magnetic field (the component perpendicular to the frontal plane). This equivalent magnetic multipole generator was found to represent the cardiac magnetic field with a minimum error of less than 10%. The dipolar term of the expansion was found to represent the field distribution with reasonable accuracy early during ventricular activation, whereas late during activation, the higher multipole terms were clearly more significant.