The authors have indicated no significant interest with commercial supporters.T he number of patients with implantable electronic devices (IEDs) is growing as indications for a myriad of cardiac and neurological disorders that cannot be managed using medication alone expand. 1 These devices include gastric and cardiac pacemakers, implantable cardioverter defibrillators, cochlear implants, and a range of stimulators of the deep brain, vagal nerve, sacral nerve, phrenic nerve, spinal cord, and bone. Encountering patients with an IED who present for office-based procedures is becoming increasingly common. Electromagnetic interference (EMI) during routine procedures has been reported to be associated with inappropriate functioning of IEDs. 2 Adverse effects of performing electrosurgery on patients with IEDs pose a patient safety risk. Medical and manufacturer reports have primarily focused on larger electrosurgical equipment used in hospitals and their effect on IEDs. Our purpose was to provide a clinical review of commonly encountered IEDs, their clinical indications, potential interference with officebased electrosurgical equipment, and recommendations to prevent complications and injury. IEDs: Clinical Indications Cardiac PacemakersAlthough pacemaker technology has advanced since the first one was implanted in 1958, 3 common indications are still symptomatic bradyarrhythmias, such as sinus node dysfunction and heart block. A pacemaker consists of a battery-powered generator connected to electronic pacing wires inserted intravenously to the right-side chambers of the heart. 4 The earliest devices were asynchronous devices, pacing the heart at a fixed rate regardless of the patient's underlying rhythm and sometimes causing symptomatic hemodynamic consequences. The latest models are demand pacemakers that sense the heart's intrinsic rhythm and inhibit pacing in the same chamber or trigger pacing in another cardiac chamber. 5,6 These devices also have sophisticated timing features to optimize heart rates and even treat some atrial arrhythmias. Implantable Cardioverter DefibrillatorsImplantable cardioverter defibrillators (ICDs) have had a profound effect on patients with ventricular tachyarrhythmias and those at risk for sudden cardiac death. 7 ICDs are programmed to treat lifethreatening ventricular arrhythmias with rapid overdrive pacing or an internal defibrillator shock. These patients most commonly have severe acquired, inherited, or idiopathic forms of cardiomyopathy. Indications continue to expand to include asymptomatic patients with low ejection fractions at risk of sudden death. Similar to pacemakers, these devices