title: The potential distribution on the epicardial surface and in the surrounding volume conductor.
abstract: An experimental study was performed on the potential distribution surrounding the heart. The dog heart was isolated, perfused with Tyrode solution and was placed in a spherical container filled with the same solution. The potential measurement was made at 156 sites on the epicardial surface as well as at the same number of locations on the corresponding surface in the solution 0.5 to 2.0 cm apart from the epicardium. The results indicated that considerable simplification of isopotential lines occurred already at a distance of 2 cm from the heart. With the electrode array on the spherical surface enclosing the heart, similar maps were constructed and an index to express the complexity of the map was calculated. With artificial extrasystoles arising from an epicardial site, the potential on the epicardium showed a main negative area with very closely located positive areas. The basis and methods for the determination of epicardial potential from the surface measurements were critically discussed.
mesh_terms: D000818:Animals; D004285:Dogs; D004562:Electrocardiography / Q000379:methods*; D004594:Electrophysiology; D006321:Heart / Q000502:physiology; D066298:In Vitro Techniques; D010477:Perfusion