Hierarchy of the heart rhythmogenesis levels is a factor in increasing the reliability of cardiac activity.

Along with the existence of an intracardiac pacemaker a generator of cardiac rhythm exists in the central nervous system - in the efferent structures of the cardiovascular center of the medullar oblongata. Neural signals originating there in the form of bursts of impulses conduct to the heart along the vagus nerves and after interaction with cardiac pacemaker structures cause generation of the cardiac pulse in exact accordance with the frequency of the neural bursts. That the intrinsic cardiac rhythm generator is a life-sustaining factor that maintains the heart pumping function when the central nervous system is in a stage of deep inhibition. The brain generator is the factor that provides the heart with adaptive reactions to changes in the environment. The hierarchy of the two duplicating levels of rhythmogenesis provides reliability and functional perfection of the cardiac rhythm generation system in the whole organism.