Abstract The cardiac conduction system is a specialized collection of cells that generate and propagate action potentials throughout the heart in order to facilitate the synchronized contraction of myocardium. The system consists of the sinoatrial (SA) node, the atrioventricular (AV) node, and the His-Purkinje system. The SA node acts as the heart’s pacemaker, generating action potentials at a rate determined by the “funny current,” a mixed sodium-potassium current that may be modulated by the autonomic nervous system. As impulses are generated along the conduction system, they pass through the AV node, where a brief delay prevents simultaneous atrial and ventricular contraction. As the action potential reaches the ventricles, the His-Purkinje system ensures synchronized ventricular depolarization in order to maximize cardiac output. Action potentials propagated along the conduction system are exquisitely regulated by varying physiologic states and neural mediators.