| a small mass of muscular fibers at the base of the wall between the atria, conducting impulses received from the sinoatrial node by way of the atrioventricular bundles and, under certain conditions, functioning for the sinoatrial node as pacemaker of the heart. Abbreviation: A-V node. |
| atrioventricular node n. A small mass of specialized cardiac muscle fibers, located in the wall of the right atrium of the heart, that receives heartbeat impulses from the sinoatrial node and directs them to the walls of the ventricles. Also called AV node. |
atrioventricular node n.
A small mass of specialized cardiac muscle fibers, located near the ostium of the coronary sinus and giving rise to the atrioventricular bundle of the conduction system of the heart. Also called A-V node.