FORWARD PROBLEM OF ELECTROCARDIOGRAPHY AND MAGNETOCARDIOGRAPHY: A CONTINUING CHALLENGE.

The solution to the forward problem of electrocardiography and magnetocardiography requires calculation of extracardiac electric and magnetic fields for given cardiac sources. In a more general sense, the forward problem is how to reproduce cardiac fields from first principles; i. e. , its solution requires simulation of the human heart's excitation. Cardiac excitation is simulated in a digital model that has the same shape and anisotropic structure as the human heart; each element of this model is an automaton which mimics the cardiac tissue's local behavior. The numerical model of an inhomogeneous torso is used to calculate extracardiac fields.