Library · Anatomy
Atrioventricular node
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The heart has the atria on top and the ventricles below. Between them there is only one normal electrical doorway, and that doorway is the atrioventricular node. It sits at the base of the right atrium, in an area doctors call the triangle of Koch.
Its job sounds strange at first: to slow things down. The electrical impulse arrives from above and the node holds it for an instant before letting it move on. That delay is not a flaw, it is the whole point. It gives the ventricles time to finish filling with blood before they contract. And if the atria start firing too fast, the node does not pass everything along: it filters.
Think of a lock on a canal, the kind that lets water through a little at a time and never all at once.
The node also has a backup job. The heart's normal pacemaker is the sinoatrial node, up top. If that one fails or becomes very slow, the atrioventricular node can take over and hold the rhythm at about forty to sixty beats per minute.
In brief
The atrioventricular node is a specialized part of the heart's conduction system, housed in the triangle of Koch at the base of the right atrium.
It is the only normal electrical connection between the atria and ventricles, and it adds a delay that improves ventricular filling and slows rapid atrial impulses.
A canal lock: water passes a little at a time, never all at once.
If the sinoatrial node fails or runs too slowly, the atrioventricular node can take over at about forty to sixty beats per minute.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingAtrioventricular Node, StatPearlsPublished
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