Editing Cardiac pacemaker (section)

===Damage to the SA node===
If the SA node does not function, or the impulse generated in the [[Sinoatrial block|SA node is blocked]] before it travels down the electrical conduction system, a group of cells further down the heart will become its pacemaker.<ref>{{EMedicine|article|155146|Junctional Rhythm}}</ref> This center is typically represented by cells inside the [[atrioventricular node]] (AV node), which is an area between the [[Atrium (heart)|atria]] and [[Ventricle (heart)|ventricles]], within the [[atrial septum]].  If the AV node also fails, [[Purkinje fibers]] are occasionally capable of acting as the default or "escape" pacemaker.