[Integral characteristics of the cardiac electric generator in the repolarization period]

Integral characteristics (dipole moment, localization of the electrical centre and complexity parameter) of cardiac electrical generator for the normal dog heart during the fast repolarization period (corresponding to the T wave of electrocardiogram) are considered. The characteristics are calculated using electrical field potentials measured on a spherical surface around the heart. It is found that during the repolarization period these characteristics change with time much less and provide more accurate description of the heart electrical state than during the depolarization period (corresponding to the QRS complex of electrocardiogram). It is shown that over all the cardiac cycle the equivalent generator having form of a single dipole localized at the moving electrical centre of the heart provides average error of potential approximation that does not exceed average random error of present electrocardiographic recording technique. In addition this model includes comparatively small number of variables and has explicit physical and physiological interpretation. Thus application of such a model for describing cardiac electrical generator is more reasonable than application of the classical multipole models of high orders.