Setting up an electrophysiology laboratory for cardiac ablations requires specifics in the layout of laboratory, personnel, and equipment requirements. Conventional electrophysiology (EP) studies and ablation procedures should be performed with adequately trained personnel. This chapter deals with the organization of an arrhythmia laboratory. An electrophysiology laboratory capable of performing EP studies and ablations must be equipped with a radiographic system including cinefluoroscopic equipment; the ability to separately monitor vital signs including the cardioverter/defibrillator and non-invasive measurements of blood pressure and pulse oximetry; and data acquisition system including the physiologic recorder. The junction boxes receive the intracardiac signals from the catheters and provide an interface into the physiologic recorder. A programmable stimulator is necessary to obtain electrophysiologic data beyond measurements of conduction intervals. Cardiac mapping is the process by which arrhythmias are characterized and localized. Conventional mapping involves acquiring electrogram data from fixed and moving catheters and creating mental activation maps with fluoroscopic two-dimensional images.