sinoatrial node


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Related to sinoatrial node: atrioventricular node, bundle of His

sinoatrial node

[¦sī·nō′ā·trē·əl ′nōd]
(anatomy)
A bundle of Purkinje fibers located near the junction of the superior vena cava with the right atrium which acts as a pacemaker for cardiac excitation. Abbreviated SA node. Also known as sinoauricular node.
References in periodicals archive ?
Under normal circumstances, the greatest automaticity is in the cells of the sinoatrial node, followed by the cells of the AVN.
Origin of the sinoatrial node and atrioventricular node arteries in right, mixed, and left inferior emphasis systems.
During an episode of atrial fibrillation, the function of the sinoatrial node is overtaken and many electrical impulses, greater than 400 per minute, fire off from the upper chambers of the heart.
The beating of the heart is controlled by electrical impulses that originate in a specialized part of the heart called the SA or sinoatrial node.
SVT is defined as "any abnormally rapid dysrhythmia that originates above the ventricles, that is, any portion of the atrium including the sinoatrial node, the atrioventricular node, or within the bundle of His proximal to its bifurcation" (Ziegler, 1994, p.
Fibrous thickening of the aortal wall can cause interference with the conduction of electrical impulses from the sinoatrial node that coordinate the intrinsic contraction of the heart muscle.
A normal heart contraction begins with an electrical signal from the sinoatrial node, a group of cells in the right atrium.
12] The normally slower heart rate may be due to immaturity of the sinoatrial node early on or the atrial pacemaker may actually be slower in early gestation.