Figure 32.1

Left: Schematic drawing of a horizontal section of the human thorax illustrating the pathway of the currents, which arise from an excitation wavefront (solid line in septum) spreading through the septum in a left-to-right direction. A indicates the area where the current lines reach the surface; B indicates the area from which the currents dip into the thorax pointing to the posterior aspect of the wavefront. Right: Potential distribution in the same thoracic section and at the same instant. The plus sign indicates the location of the potential maximum on the surface (corresponding to point A); the minus sign indicates the location of the potential minimum (corresponding to point B).