Alternative View on the Mechanism of Cardiac Rhythmogenesis

Abstract Background: This article advances an hypothesis that there is duplication of the heart rhythmogenesis system. Methods and Results: The following article reviews available data and advances an hypothesis to suggest new ideas about the mechanisms of cardiac rhythm generation. The hypothesis is that along with the existence of an intracardiac pacemaker, the generator of cardiac rhythm exists in the central nervous system - in the efferent structures of the cardiac centre of the medulla oblongata. Originating in the medulla oblongata, neural signals in the form of brief bursts of pulses are conducted to the heart along the vagus nerves and, by interacting with the cardiac pacemaker structures, cause generation excitement in the heart in exact accordance with the frequency of the bursts. The intracardiac rhythm generator is a life-providing factor that maintains the heart pumping function when the central nervous system is in a stage of deep inhibition (e.g. under anaesthesia or when unconscious). The central generator is the factor that provides the heart with adaptive reactions in natural conditions of the organism. Conclusions: Multi-leveled organisation of the mechanisms responsible for rhythmogenesis guarantees reliability and functional perfection of the cardiac rhythm generation system.