The human heart contains a specialized conduction system through which it can create and transmit electrical impulses without any external neural input. The main components of the conduction system of the heart include the SA node, AV node, Bundle of His and the Purkinje fibers. The sinoatrial node (also known as SA node) is a natural pacemaker and is responsible for depolarization of the right and left atrium. This produces a P wave on the EKG reading which is normally 0.1 second and its normal amplitude is 0.10-.012 mV. The AV node then causes a brief delayed of 0.1 second which allows the ventricles to relax and fill with blood. The AV node then transmits electrical signals from the atrium to the ventricles through the interventricular septum.