A Study of the Relationship between Unipolar Leads and Spatial Vectorcardiograms

The extent to which precordial and other unipolar leads are influenced by the proximity of the exploring electrode to one part or another of the heart is the subject of considerable debate. One approach to the problem is to determine how closely precordial leads can be predicted from spatial vectorcardiograms recorded by leads relatively remote from the heart. The panoramic vectors cardiograph described below provides a convenient way of doing this, since it automatically records scalar derivations from the vectorcardiogram for any spatial axis. Results indicate that local effects are not the predominant factor in determining the form of the complexes in precordial leads.