Intrinsic properties of uncorrected and highly corrected leads.

IT has become increasingly evident during the past several years that the single, fixedlocation dipole generator serves only as a firstorder approximation in accounting for the distribution of electrocardiographic potentials over the body surface.' 3 In principle any desired degree of approximation may be achieved by superimposing multipolar equivalent generators of higher order upon the dipole.4 5 Roughly speaking, generators of the second order (quadripoles) represent dislocation of the heart's electrical center from the origin of the reference system whereas thirdorder (octapolar) behavior is due largely to the spreading out of dipolar elements into one or more electromotive surfaces. Ideal vectorcardiographic leads may be defined as those capable of responding accurately and exclusively to the dipolar components of the equivalent cardiac generator. In a previous study6 we were able to demonstrate sizable deviations from the ideal situation in several leads of three corrected vectorcardiographic systems.7 Subsequent refinements in experimental technique now permit us to extend the original method of lead analysis to ordinary electrocardiographic and uncorrected vectorcardiographic connections. Further developments in data handling have also resulted in the construction of new, highly corrected anteroposterior and transverse connections whose properties closely approximate those of the corresponding ideal vectorcardiographic leads.