Nonuniform Recovery of Excitability in Ventricular Muscle

Recovery of excitability of ventricular muscle was measured at numerous points in exposed dog ventricles at varying distances along six radial axes from a primary point of stimulation. Temporal dispersion of recovery of excitability at various points equidistant from the point of stimulation was minimal after a basic beat but was increased after an early premature beat. The degree of dispersion following a basic beat was increased by stimulation of the cardiac sympathetic nerves, administration of chloroform, ouabain intoxication, administration of higher doses of quinidine, myocardial ischemia, and hypothermia, but it was decreased by administration of sympathomimetic amines.