The elements of electrocardiographic theory

A survey of some of the more important theoretical ideas of electrocardiography is presented for the consumption of the electrical engineer. The development, importance, and objectives of electrocardiography are discussed briefly, followed by a description of the electrical activity of the human heart and the potentials it produces at the surface of the body. Standard connections used in electrocardiography are described. A simplified theory is developed based upon a homogeneous, spherical conducting model containing a current dipole at its center, and the weakness of the assumptions on which it is based is pointed out. The concept and use of the heart vector is treated and methods of portraying heart-vector functions, similar to impedance functions, are illustrated. A limited description is given of the new field of vectorcardiography.