The Atrio-Ventricular Node

The atrioventricular node introduces a delay in conduction which allows atrial contraction to fill the relaxed ventricles before ventricular contraction pushes blood around the body. It also acts as a gate to prevent the ventricles from contracting too rapidly in response to atrial arrhythmias.

Atrioventricular block describes a partial or total interruption of the conduction of electrical impulses from the atria to the ventricles. It is classified as follows:

Block can also occur below the atrioventricular node and the bundle of His, within the left and/or right bundle branches. This is referred to as bundle branch block.

Arrhythmias starting within, or near to, the atrioventricular node are normally classified as supraventricular arrhythmias, the most common of which is atrioventricular nodal reentrant tachycardia.