Biomaterial Database

Hierarchy of supraventricular pacemakers. 1981

W C Randall, and W H Wehrmacher, and S B Jones

Definitive subsidiary atrial pacemakers (SAPs) exist within the crista terminalis and in the atrial free wall tissue at the junction of the inferior vena cava and the inferior right atrium. These pacemakers are capable of maintaining cardiac rhythm at a rate intermediate between that of the sinoatrial (SA) nodal and atrioventricular (AV) junctional pacemakers upon default of the normal SA nodal cells. The conventional concept of a single (junctional) escape mechanism needs to be updated by recognition of these SAP sites, which are under comprehensive autonomic regulation. A great variety of clinically important cardiac syndromes require understanding of the SAPs, not only for diagnostic significance but also for therapeutic consideration. SAPs differ from the SA pacemakers in that they possess intrinsically slower spontaneous rates and are less stable. There is early competition among them for instantaneous dominance. They are more responsive to both sympathetic and parasympathetic control, and they are initially more susceptible to underdrive stimulation by another pacemaker (whether artificial or natural) than are pacemakers with the SA node.

UI	MeSH Term	Description	Entries
D010275	Parasympathetic Nervous System	The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.	Nervous System, Parasympathetic,Nervous Systems, Parasympathetic,Parasympathetic Nervous Systems,System, Parasympathetic Nervous,Systems, Parasympathetic Nervous
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D006329	Heart Conduction System	An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.	Conduction System, Heart,Conduction Systems, Heart,Heart Conduction Systems,System, Heart Conduction,Systems, Heart Conduction
D006339	Heart Rate	The number of times the HEART VENTRICLES contract per unit of time, usually per minute.	Cardiac Rate,Chronotropism, Cardiac,Heart Rate Control,Heartbeat,Pulse Rate,Cardiac Chronotropy,Cardiac Chronotropism,Cardiac Rates,Chronotropy, Cardiac,Control, Heart Rate,Heart Rates,Heartbeats,Pulse Rates,Rate Control, Heart,Rate, Cardiac,Rate, Heart,Rate, Pulse
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001283	Atrioventricular Node	A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.	AV Node,A-V Node,Atrio-Ventricular Node,A V Node,A-V Nodes,AV Nodes,Atrio Ventricular Node,Atrio-Ventricular Nodes,Atrioventricular Nodes,Node, A-V,Node, AV,Node, Atrio-Ventricular,Node, Atrioventricular,Nodes, A-V,Nodes, AV,Nodes, Atrio-Ventricular,Nodes, Atrioventricular
D012849	Sinoatrial Node	The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).	Sinuatrial Node,Sinus Node,Sino-Atrial Node,Sinu-Atrial Node,Node, Sino-Atrial,Node, Sinoatrial,Node, Sinu-Atrial,Node, Sinuatrial,Node, Sinus,Nodes, Sino-Atrial,Nodes, Sinoatrial,Nodes, Sinu-Atrial,Nodes, Sinuatrial,Nodes, Sinus,Sino Atrial Node,Sino-Atrial Nodes,Sinoatrial Nodes,Sinu Atrial Node,Sinu-Atrial Nodes,Sinuatrial Nodes,Sinus Nodes
D013564	Sympathetic Nervous System	The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.	Nervous System, Sympathetic,Nervous Systems, Sympathetic,Sympathetic Nervous Systems,System, Sympathetic Nervous,Systems, Sympathetic Nervous
D016275	Atrial Function	The hemodynamic and electrophysiological action of the HEART ATRIA.	Atrial Functions,Function, Atrial,Functions, Atrial