The electrical relay station between the upper and lower chambers of the heart: "Electrical signals from the atria (upper chambers) must pass through the atrioventricular node in order to reach the ventricles (two lower chambers of the heart)."

"The atrioventricular note, or AV node, which controls the heart rate, is one of the major elements in the cardiac conduction system (specialized tissue that carries bodily electrical impulses)."