Current status of body surface electrocardiographic mapping.

BODY SURFACE electrocardiographic mapping is a unique approach for recording, displaying, and analyzing the cardiac electrical field. Studies undertaken by numerous investigators during the past two decades have provided a sound physiologic basis for this method and have developed the techniques required to make it clinically applicable. It is the purpose of this Editorial to review the basic foundations of surface mapping, to describe its successes in selected clinical applications, and to discuss certain technical and conceptual barriers to its widespread implementation. Four interrelated advantages of body surface electrocardiographic mapping are listed in table 1. The first is the ability to correlate body surface and epicardial events. As stated by Wilson et al.' in 1934, unipolar torso leads "are in reality semi-direct leads from the ventricular surface, capable within certain limits of serving the same purposes as direct leads from . . . the exposed heart." The net result, as stated succinctly by Spach and Barr,2 is that "the strength of the surface map is the direct association of the areas of positive and negative surface potentials with major wavefronts of the heart." Experimental and clinical studies have consistently substantiated these claims. Surface patterns can reliably localize single epicardial events, including artificial pacemaker stimuli and experimentally produced burns as well as epicardial wavefronts during normal atrial and ventricular activation. Multiple, simultaneously active events can also be detected if the sources are sufficiently separate in distance and orientation. This first and most general advantage is the direct consequence of the next two attributes of surface mapping. Because electrocardiographic potentials are recorded from large areas of the chest, body surface