An analog computer has been built which determines (e12+e22)½and Arc Tane2/e1two thousand times a second with an accuracy of about five percent. Using amplified electrocardiographic voltages proportional to three perpendicular components of the dipole moment of the hearts electric field, a pair of computers of this type will be able to produce other voltages proportional to the magnitude and two directional angles of the dipole. This may simplify considerably the study of fluctuations in the direction of the dipole and the neutralization of the effects of abnormal heart positions.