Selective Stimulation of Intra-cardiac Postganglionic Fibres

Abstract

IT was observed by Lewis et al.¹ that the duration of the refractory period of the electrically stimulated auricles may be increased by atropine. They believed that the effect may be ascribed to the stimulation of the intra-auricular parasympathetic fibres by the driving stimuli. Since that report, the effects of the stimulation of the intra-cardiac parasympathetic and/or sympathetic nerve fibres superimposed on the effect of stimulation of the heart muscle or sino-auricular node have been observed by other authors^2–4. Brady et al.⁵ described the inotropic effect of series of impulses applied during the refractory period of the cardiac muscle.