Atrioventricular node

The atrioventricular node (abbreviated AV node) is the part of the control system that electrically connects the atrial (upper) and ventricular (lower) chambers of the heart. Electrical signals from the atria must pass through the AV node to reach the ventricles. The conductive system is organized so that transmission is slightly delayed at the atrioventricular node, thus allowing time for the atria to fully contract before the ventricles are stimulated.