Evaluating the Effects of Different Dental Devices on Implantable Cardioverter Defibrillators Kanwal R. Maheshwari, BDS,* Kian Nikdel, DDS,* Girard Guillaume, PhD, † Ariadne M. Letra, DDS, MS, PhD,* Renato M. Silva, DDS, MS, PhD,* and Samuel O. Dorn, DDS* Abstract Introduction: The implantable cardioverter defibril- lator (ICD) is an electronic device that emits electrical signals to the heart via lead wires and electrodes. It is used for cardiac rhythm monitoring and treatment. Because electronic dental devices have been shown to produce electromagnetic fields, we hypothesize that they may interfere with ICD function. Methods: Nine dental devices (heat carrier, electronic apex locator, electric pulp tester, unipolar electrosurgery unit, electric motor, curing light, and 3 gutta-percha guns) were tested in this study for their ability to inter- fere with the function of 4 ICDs (2 single-chambered and 2 dual-chambered ICDs). ICD activity was moni- tored for 30 seconds using an ICD programmer (Med- tronic 2090; Minneapolis, MN) and evaluated through an electrogram test strip printout. Results: Electromagnetic interference was detected with the electric motor, curing light, electric pulp tester, and electrosurgery unit although no electromagnetic disturbances were detected with these devices. No electromagnetic interferences were observed for the gutta-percha guns, heat carrier, and apex locator. However, the electrosurgery unit affected the dual- chambered ICD (Consulta CRT-D, Medtronic) and delivered therapies for fibrillation when no ventricular fibrillation was present. Conclusions: Our results suggest that the electrosurgery unit produces electromagnetic disturbances with unwanted therapy delivery shock and potentially clinically significant outcomes. (J Endod 2015;41:692–695) Key Words Electromagnetic disturbance, electromagnetic interfer- ence, electronic dental devices, implantable cardioverter defibrillator T he implantable cardioverter defibrillator (ICD) is an electronic device that emits electrical signals to the heart by electrodes and lead wires through which the car- diac rhythm is monitored, and treatment, when indicated, is delivered by sending electrical charges to the heart. ICDs are surgically placed under the skin, usually near the left clavicle. They have flexible insulated lead wires that run through the veins to the heart and monitor the heart rate continuously to detect heart rhythm disorders (arrhythmias). There are 3 basic kinds of heart arrhythmias: the heart rate could either be too slow (bradycardia), too fast (tachycardia), or irregular (1). When an arrhythmia is detected, the ICD delivers a precisely calibrated electri- cal shock to terminate the arrhythmia and restore the normal heart rhythm. Today, ICDs are placed in more than 60,000 people annually in the United States (2). A previous study by Pinski and Trohman (3) suggested that ICDs are potentially sensitive to electromagnetic interference (EMI) from external sources. Manufac- turers have issued precautions for patients with ICDs in relation to EMI that may result in symptoms such as light-headedness, increased heart rate, and a defibrilla- tion shock and patients who hear beeping tones from their device (4, 5). Niehaus and Tebbenjohanns (6) state no special precautions for pacemaker and ICD patients in the use of common household equipment, airport screening devices, and cellular phones, but they report a contraindication to undergo magnetic resonance imaging and close proximity to electronic article surveillance systems. Niehaus and Tebben- johanns also state that a cumulative dose on the ICDs and pacemakers above 5 Gy in connection with radiotherapy should be avoided, and if the dose has exceeded 5 Gy, then the pacemaker or ICD should be exchanged after radiotherapy (6). ICD pa- tients should be programmed to detection-off or temporarily inactivated using a pacemaker magnet on the condition that monitoring and an external defibrillator are available before the use of electrocautery devices (6). Earlier studies examined EMI of dental devices on pacemakers and ICDs. Roedig et al (7) tested 9 dental devices for their ability to interfere with a pace- maker, an ICD, and a biventricular ICD in vitro. Their results showed that the operation of both an ultrasonic scaler and a battery-operated composite curing light interfered with the pacing function of ICDs. The use of an ultrasonic scaler inhibited pacing at 7 cm from the leads, whereas the use of the battery-operated composite curing light inhibited pacing function only at 2 to 3 cm from the leads. Garofalo et al (8) tested 5 electronic apex locators (EALs) on pacemakers in vitro, and only 1 EAL (Bingo; Dent Corp, White Plains, NY) interfered with pacemaker function. A number of studies have examined the use of different dental devices in patients with pacemakers and suggest that they do not present harm to patients (9–12). Brand et al (13) tested 10 dental devices for their ability From the *Department of Endodontics, School of Dentistry, University of Texas Health Science Center at Houston, Houston, Texas; and † Medtronics, Inc, Minneapolis, Minnesota. Address requests for reprints to Dr Samuel O. Dorn, Department of Endodontics, University of Texas School of Dentistry, 7500 Cambridge Street, Suite 6400, Houston, TX 77054. E-mail address: samuel.o.dorn@uth.tmc.edu 0099-2399/$ - see front matter Copyright ª 2015 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2014.12.011 Basic Research—Technology 692 Maheshwari et al. JOE — Volume 41, Number 5, May 2015