(see also Ablation)

Electrophysiology studies (EPS) are performed in a specialized lab to determine an arrhythmia diagnosis or an EP mechanism of a known arrhythmia. They provide a valuable adjunct to the traditional 12-lead EKG, Holter monitor, and stress test. The preparation for an EPS is similar to that for cardiac catheterization. The patient is given nothing by mouth and is sedated during the procedure. A peripheral IV is necessary to administer medication, and systemic anticoagulation may be used. During the procedure, transvenous intracardiac catheters are placed (with the aid of fluoroscopy) into various locations of the heart. These catheters allow recording of intracardiac action potentials and programmed electrical stimulation (PES). Lethal dysrhythmias may be induced; therefore, the procedure is performed in an environment where resuscitative equipment is readily available. Complications are rare but include hematoma, pneumothorax, deep vein thrombosis, stroke, and sudden death.