What is the electrical conducting pathway through the heart?

The heart is myogenic meaning that impulses (action potentials) are stimulated from the pacemaker cells of the heart. These action potentials are initiated from the sinoatrial node (SAN) which are a cluster of cells located in the upper wall of the right atrium. These calls propagate the signal to the AV node at the bottom of the atria causing it to contract. The AV node causes a short delay in the electrical impulse so that the atria can fully contract and empty before propagating the impulse down the Bundle of His in the ventricles. The electrical impulse travels down these fibres and divides into Purkinje fibres which cause the ventricles to contract from the apex upwards. This allows blood to be sent out of the heart to the lungs and the rest of the body.