An EPS provides valuable information about cardiac arrhythmias by recording intracardiac electrograms and using programmed stimulation techniques. Although the sequence of study protocols may vary with each institution, an EPS routinely begins with baseline measurement of conduction intervals. Subsequently, clinical arrhythmias are induced either by incremental or decremental pacing and extrastimulus techniques. Nurses must understand the technical and psychosocial aspects of an EPS to ensure adequate care. The primary role of nurses is to maintain a safe environment for the patient in the electrophysiology laboratory (i.e., maintain aseptic techniques and intervene when complications occur). Rapid technological advances and the increasing number of well-educated patients require that nurses be knowledgeable and skilled in providing progressive care, such as developing educational programs and support groups for patients and patients' families.