7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Official reprint from UpToDate www.uptodate.com 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment : Mark S Link, MD : N A Mark Estes, III, MD : Nisha Parikh, MD, MPH All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Jun 2023. This topic last updated: Mar 22, 2023. INTRODUCTION While there has always been concern about the potential for electromagnetic interference (EMI) with pacemaker, implantable cardioverter-defibrillator (ICD), and cardiac resynchronization devices function due to interaction between the device and an electromagnetic field, the risk is generally low, unless there is a strong magnet or electrical field close to the generator ( table 1) [1,2]. EMI can occur in a variety of settings, but overall is more likely in the hospital environment than in the nonhospital environment [3]. There are reports of cardiac implantable electronic devices (CIEDs) being impacted by sources of EMI in the nonhospital environment (eg, strong magnets, cellular phones, slot machines, laptop computers, etc). There are also disclaimers that wireless sources could be the source of EMI with CIEDs, even though no published data exists (eg, automobile manufacturers providing "caution" for device patients purchasing automobiles with "keyless" entry mechanisms, hybrid engines, etc). Nonetheless, most sources of EMI in the nonhospital environment are not concerning [4,5]. However, with the proliferation of wireless technology, any new device which operates on a new frequency or new technology platform should be assessed for the likelihood of clinically significant EMI. Electromagnetic interference with medical sources is discussed separately. (See "Pacing system malfunction: Evaluation and management", section on 'Electromagnetic interference' and https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 1/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate "Cardiac implantable electronic devices: Long-term complications", section on 'Electromagnetic interference'.) HOUSEHOLD APPLIANCES Although there are no studies that have systematically evaluated the effect of household microwave ovens on implanted devices, it is widely accepted that contemporary pacemakers and ICDs are adequately shielded from microwave energy produced by modern appliances [3]. Manufacturers do not recommend any special precautions when using common household appliances, such as televisions, radios, toasters, microwave ovens, and electric blankets; UpToDate experts agree with this approach. As a new appliance that uses a new or different energy source reaches the market, the appliance needs to be tested to determine whether there is any potential for device interference. There are circumstances in which a device may be affected by specific sources of energy under narrow circumstances. This was illustrated in a study assessing the potential for induction cook tops to interfere with pacemaker function. Patients with a unipolar, left-sided implant could experience interference if the pot was not concentrically placed on the induction coil and if the patient stood as close as possible to the cook top. The most common response to interference was a reset to an asynchronous interference mode [6]. Most contemporary devices utilize bipolar pacing and sensing configuration, which minimizes the chance of device malfunction from electromagnetic interference. CELLULAR TELEPHONES The widespread use of cellular telephones requires a heightened awareness of their potential for adverse effects on cardiac device function. Equipment with high-strength magnets Patients with a pacemaker or an ICD should be aware that strong magnetic fields in close proximity to their device generator can alter normal cardiac device function [7-10]. Electronic equipment (eg, cellular phones with strong magnets for wireless charging) and accessories with powerful magnets (eg, watch bands) should be stored at least 15 inches away from pacemaker or ICD generators ( figure 1 and picture 1). In general, we advise all patients to use cellular telephones at the ear on the side opposite the cardiac device and carry cellular telephones in a pocket below the waist. Similar warnings apply to magnets included in clothing, accessories, and elsewhere. (See 'Small magnets incorporated into clothing, furniture, and identification badges' below.) https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 2/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate When equipment with a strong magnetic field is in close proximity to an ICD or pacemaker generator, the cardiac device defaults to magnet mode. Generally, magnet mode causes ICDs to suspend tachyarrhythmia therapies (eg, shocks and antitachycardia pacing) until the magnet is removed. Magnet mode causes pacemakers to asynchronously pace at rates and modes determined by the type of device and manufacturer ( table 2). (See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator", section on 'Magnet application' and "Pacing system malfunction: Evaluation and management", section on 'Magnet application'.) While there are too many devices and magnet applications to provide a complete list of equipment and scenarios to avoid, the following case reports highlight specific devices and use scenarios that may induce magnet mode in an ICD or pacemaker: Working with a laptop on the chest while recumbent [7]. Using a wristwatch with a magnetic band [11]. Using a cellular phone with a magnetic array for wireless charging (eg, iPhone 12) [8]. Large interrogation studies describe the rate of unintended magnet mode induction (events) as between 7 and 11 events per 100 patient years [9,12]. Neither study recorded malignant arrythmias during magnet mode induction, suggesting that most magnet mode activations were short-lived. Equipment without high-strength magnets Cellular telephone equipment without strong magnets is unlikely to cause clinically significant interference with pacemakers or ICDs [13-18]. However, cellular phones may disrupt telemetry, and patients should avoid using the cellular phone during telemetry [19]. In addition, patients should use the telephone at the ear on the side opposite the cardiac device and carry the telephone in a pocket below the waist. Use on the contralateral side will maximally reduce the risk of interference [20,21]. SECURITY SYSTEMS Electromagnetic security systems (eg, antishoplifting gates, metal detectors) are in widespread use, and are often present in or near the workplace, in shopping malls, and at airports. Although device interference is possible, it is unlikely that any clinically significant interference would occur with the transient exposure associated with walking through such a field. There are case reports of inappropriate shocks and pacemaker inhibition associated with continued close exposure to electromagnetic security systems [22]. The best recommendation for patients is to move through the detection and do not stop close to the detectors (ie, be aware of the location https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 3/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate of security systems and simply move through them at a normal pace) [1]. Single-beat inhibition of a device by anti-theft equipment would not be of clinical concern. Permanent pacemakers Electronic security systems can potentially interfere with pacemakers [23-25]. The frequency and type of complications were evaluated in a study of 204 patients who were exposed to an electronic security system for up to 30 seconds [23]. One or more episodes of pacemaker function interference developed in 17 percent of patients. Sensing abnormalities were the most common type of interference, and they were typically transient, lasting only for the duration of exposure. In patients with dual chamber pacemakers, interference at the atrial level was more common than at the ventricular level. In another report, the most common complications were asynchronous pacing, atrial oversensing (producing a tachycardia in the ventricle), ventricular oversensing (with pacemaker inhibition), and paced beats due to direct induction of current in the pacemaker [24]. Symptoms such as palpitations and presyncope occurred in some patients while they were in the security system field. Interference with pacemaker function can occur at a distance of 50 cm from the security system [25]. This is of particular concern for those who are fully pacemaker-dependent; such patients should avoid remaining in close proximity to a security system. General consensus is that it is safe for airport personnel to use a hand held metal detector or 'wand' for patients with a permanent pacemaker, even for those who are pacemaker-dependent. Additionally, a manual or pat-down search can be performed [1]. Implantable cardioverter-defibrillators There are case reports of a patient with an ICD in whom interference from an electronic antitheft-surveillance device resulted in the delivery of multiple shocks due to oversensing [22,26]. In contrast, no interference was noted in another report of 25 patients with an ICD who were exposed to the fields of six different electronic article surveillance systems using three modes of operation (magnetic audio frequency, radiofrequency, or acoustomagnetic) [24]. The duration of exposure is an important determinant of risk as illustrated in a study of 170 patients with variable exposure to three common systems [27]. This again emphasizes the basic principle of "move through the detection and do not stop close to the detectors." General consensus is that it is safe for airport personnel to use a hand held metal detector or 'wand' for patients with a ICD. Additionally, a manual or pat-down search can be performed [1]. EXTERNAL ELECTRICAL EQUIPMENT https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 4/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Potential causes of concern in the workplace are welders, industrial welding machines, electric motors, and degaussing coils [1,28]. Functional evaluation of pacemakers and ICDs in the work place has rarely demonstrated oversensing of an external electrical field. Nevertheless, since interference remains a concern, it is recommended that assessment of potential electromagnetic sources in the workplace be considered when the patient returns to work. For the non-pacemaker dependent patient this should rarely, if ever, be a problem. For the pacemaker-dependent and/or ICD patient it may be necessary to monitor the patient with an ambulatory monitor to determine if proximity to and/or use of specific equipment results in any interference. Rarely, for patients that are felt to be at higher risk or using equipment that is known to generate higher electromagnetic fields, it may be necessary to have the work environment assessed by an occupational safety officer or engineer prior to return to work [1]. LEAKAGE OF CURRENT FROM ELECTRICAL EQUIPMENT DRIVEN BY A POWER LINE Depending on the environment the patient is in, several scenarios could be considered. There has been concern raised regarding the potential for interference in CIED patients living under or near commercial power-lines. There is no sound evidence that any significant interference occurs in this situation [29]. For monitoring or therapeutic purposes, a patient may be connected to electromechanical equipment that is connected to a power-line. Such connections may permit accidental flow or leakage of weak alternating current through patients to ground. Similarly, an intracardiac catheter may provide a low-resistance path to ground through the patient's heart and thereby place the patient at risk for electrically induced ventricular tachyarrhythmia [30]. As previously noted, faulty household appliances have the potential for causing interference in patients with a CIED. Similarly, there have been multiple reports of CIED interference from a nongrounded or current-leaking light in swimming pools [31]. TRANSCUTANEOUS MUSCLE/NERVE STIMULATORS There are several case reports of electromagnetic interference resulting from transcutaneous muscle or nerve stimulation which caused inappropriate ICD discharges [32]. However, for many patients with implantable devices a transcutaneous stimulator can be used. For the pacemaker dependent and/or ICD patient, a monitored in-clinic assessment while operating the stimulator in the desired location should be considered prior to allowing the patient to use the equipment. https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 5/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate It should be noted that commercial transcutaneous stimulators such as those used in doctor and chiropractor offices use larger currents and thus are more likely to cause interference. SMALL MAGNETS INCORPORATED INTO CLOTHING, FURNITURE, AND IDENTIFICATION BADGES Patients occasionally ask about the use of magnets that have been incorporated into clothing, jewelry, furniture (specifically mattresses), and identification badges. While there could be potential for electromagnetic interference with a CIED, it would be dependent on the strength of the magnet. There is a relative paucity of published literature, although there are case reports of small magnets in a variety of devices (eg, snaps sewn inside a patient's jacket, continuous positive airway pressure mask for sleep apnea, etc) resulting in interference and audible alerts from an ICD [33-36]. In general, there is minimal to no concern unless a strong magnet is positioned directly adjacent to the CIED; strong magnets can induce magnet mode in pacemakers and ICDs. (See 'Equipment with high-strength magnets' above.) MAGNETIC RESONANCE IMAGING Issues relating to magnetic resonance imaging and cardiac devices are discussed separately. (See "Patient evaluation for metallic or electrical implants, devices, or foreign bodies before magnetic resonance imaging", section on 'Cardiovascular implantable electronic device'.) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 6/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Basics topic (see "Patient education: Pacemakers (The Basics)") Beyond the Basics topic (see "Patient education: Pacemakers (Beyond the Basics)") Basics topic (See "Patient education: Implantable cardioverter-defibrillators (The Basics)".) Beyond the Basics topic (See "Patient education: Implantable cardioverter-defibrillators (Beyond the Basics)".) SUMMARY AND RECOMMENDATIONS Background While there is the potential for electromagnetic interference with pacemaker, implantable cardioverter-defibrillator (ICD), and cardiac resynchronization devices function in the nonhospital environment, the risk of a clinically significant problem is generally low. (See 'Introduction' above.) Household appliances Pacemaker manufacturers do not recommend any special precautions when using normally functioning common household appliances, such as televisions, radios, toasters, microwave ovens, and electric blankets. UpToDate experts agree with this approach. (See 'Household appliances' above.) Cellular telephones Patients with a pacemaker or an ICD should be aware that strong magnetic fields (eg, selected cellular phones [iPhone 12], magnetic accessories) in close proximity to their device generator ( figure 1 and picture 1) can alter normal cardiac device function. Cellular telephone equipment without strong magnets is unlikely to cause clinically significant interference with pacemakers or ICDs. The safest strategy is for all patients to use cellular telephones at the ear on the side opposite the cardiac device and carry the telephones in a pocket below the waist. (See 'Cellular telephones' above.) Security systems While inappropriate ICD shocks and pacemaker inhibition have been associated with prolonged exposure to electromagnetic security systems (eg, antishoplifting gates, metal detectors), similar problems are only rarely seen in brief exposure. Patients should be advised to be aware of the location of security systems and to move through them at a normal pace (ie, "don't linger, don't lean"). (See 'Security systems' above.) Issues relating to magnetic resonance imaging and cardiac devices are discussed separately. (See "Patient evaluation for metallic or electrical implants, devices, or foreign bodies before magnetic resonance imaging", section on 'Cardiovascular implantable electronic device'.) https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 7/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate ACKNOWLEDGMENT The UpToDate editorial staff thank David L Hayes, MD, who contributed to earlier versions of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Pinski SL, Trohman RG. Interference in implanted cardiac devices, Part I. Pacing Clin Electrophysiol 2002; 25:1367. 2. Kolb C, Zrenner B, Schmitt C. Incidence of electromagnetic interference in implantable cardioverter defibrillators. Pacing Clin Electrophysiol 2001; 24:465. 3. Goldschlager N, Epstein A, Friedman P, et al. Environmental and drug effects on patients with pacemakers and implantable cardioverter/defibrillators: a practical guide to patient treatment. Arch Intern Med 2001; 161:649. 4. Napp A, Stunder D, Maytin M, et al. Are patients with cardiac implants protected against electromagnetic interference in daily life and occupational environment? Eur Heart J 2015; 36:1798. 5. Misiri J, Kusumoto F, Goldschlager N. Electromagnetic interference and implanted cardiac devices: the nonmedical environment (part I). Clin Cardiol 2012; 35:276. 6. Irnich W, Bernstein AD. Do induction cooktops interfere with cardiac pacemakers? Europace 2006; 8:377. 7. Tiikkaja M, Aro A, Alanko T, et al. Inappropriate implantable cardioverter-defibrillator magnet-mode switch induced by a laptop computer. Pacing Clin Electrophysiol 2012; 35:e177. 8. Greenberg JC, Altawil MR, Singh G. Letter to the Editor-Lifesaving therapy inhibition by phones containing magnets. Heart Rhythm 2021; 18:1040. 9. von Olshausen G, Schorr J, Grebmer C, et al. Incidence of magnet mode in patients with implantable cardioverter defibrillators. J Interv Card Electrophysiol 2019; 56:335. 10. Shea JB, Aguilar M, Sauer WH, Tedrow U. Unintentional magnet reversion of an implanted cardiac defibrillator by an electronic cigarette. HeartRhythm Case Rep 2020; 6:121. 11. Asher EB, Panda N, Tran CT, Wu M. Smart wearable device accessories may interfere with implantable cardiac devices. HeartRhythm Case Rep 2021; 7:167. https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 8/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate 12. Kolb C, Deisenhofer I, Weyerbrock S, et al. Incidence of antitachycardia therapy suspension due to magnet reversion in implantable cardioverter defibrillators. Pacing Clin Electrophysiol 2004; 27:221. 13. Irnich W, Batz L, M ller R, Tobisch R. Electromagnetic interference of pacemakers by mobile phones. Pacing Clin Electrophysiol 1996; 19:1431. 14. Hayes DL, Wang PJ, Reynolds DW, et al. Interference with cardiac pacemakers by cellular telephones. N Engl J Med 1997; 336:1473. 15. Ismail MM, Badreldin AM, Heldwein M, Hekmat K. Third-generation mobile phones (UMTS) do not interfere with permanent implanted pacemakers. Pacing Clin Electrophysiol 2010; 33:860. 16. Barbaro V, Bartolini P, Bellocci F, et al. Electromagnetic interference of digital and analog cellular telephones with implantable cardioverter defibrillators: in vitro and in vivo studies. Pacing Clin Electrophysiol 1999; 22:626. 17. Chiladakis JA, Davlouros P, Agelopoulos G, Manolis AS. In-vivo testing of digital cellular telephones in patients with implantable cardioverter-defibrillators. Eur Heart J 2001; 22:1337. 18. Lacour P, Parwani AS, Schuessler F, et al. Are Contemporary Smartwatches and Mobile Phones Safe for Patients With Cardiovascular Implantable Electronic Devices? JACC Clin Electrophysiol 2020; 6:1158. 19. Occhetta E, Plebani L, Bortnik M, et al. Implantable cardioverter defibrillators and cellular telephones: is there any interference? Pacing Clin Electrophysiol 1999; 22:983. 20. Hayes DL, Carrillo RG, Findlay GK, Embrey M. State of the science: pacemaker and defibrillator interference from wireless communication devices. Pacing Clin Electrophysiol 1996; 19:1419. 21. Fetter JG, Ivans V, Benditt DG, Collins J. Digital cellular telephone interaction with implantable cardioverter-defibrillators. J Am Coll Cardiol 1998; 31:623. 22. Gimbel JR, Cox JW Jr. Electronic article surveillance systems and interactions with implantable cardiac devices: risk of adverse interactions in public and commercial spaces. Mayo Clin Proc 2007; 82:318. 23. Mugica J, Henry L, Podeur H. Study of interactions between permanent pacemakers and electronic antitheft surveillance systems. Pacing Clin Electrophysiol 2000; 23:333. 24. McIvor ME, Reddinger J, Floden E, Sheppard RC. Study of Pacemaker and Implantable Cardioverter Defibrillator Triggering by Electronic Article Surveillance Devices (SPICED TEAS). Pacing Clin Electrophysiol 1998; 21:1847. https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 9/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate 25. Wilke A, Kruse T, Hesse H, et al. Interactions between pacemakers and security systems. Pacing Clin Electrophysiol 1998; 21:1784. 26. Santucci PA, Haw J, Trohman RG, Pinski SL. Interference with an implantable defibrillator by an electronic antitheft-surveillance device. N Engl J Med 1998; 339:1371. 27. Groh WJ, Boschee SA, Engelstein ED, et al. Interactions between electronic article surveillance systems and implantable cardioverter-defibrillators. Circulation 1999; 100:387. 28. Fetter JG, Benditt DG, Stanton MS. Electromagnetic interference from welding and motors on implantable cardioverter-defibrillators as tested in the electrically hostile work site. J Am Coll Cardiol 1996; 28:423. 29. Korpinen L, Kuisti H, Elovaara J, Virtanen V. Cardiac pacemakers in electric and magnetic fields of 400-kV power lines. Pacing Clin Electrophysiol 2012; 35:422. 30. Verma KP, Adam D. An unusual source of electromagnetic interference. Pacing Clin Electrophysiol 2018; 41:1381. 31. Roberto ES, Aung TT, Hassan A, Wase A. Electromagnetic Interference from Swimming Pool Generator Current Causing Inappropriate ICD Discharges. Case Rep Cardiol 2017; 2017:6714307. 32. Marbach JA, Yeo C, Green MS, Nair GM. Multiple inappropriate implantable cardiac defibrillator therapies in rapid succession. Clin Case Rep 2017; 5:1972. 33. Wolber T, Ryf S, Binggeli C, et al. Potential interference of small neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators. Heart Rhythm 2007; 4:1. 34. Schwartz Y, Wasserlauf J, Sahakian AV, Knight B. Inappropriate activation of pacemaker magnet response mode by CPAP masks. Pacing Clin Electrophysiol 2019; 42:1158. 35. Zaphiratos V, Donati F, Drolet P, et al. Magnetic interference of cardiac pacemakers from a surgical magnetic drape. Anesth Analg 2013; 116:555. 36. Beinart R, Guy ML, Ellinor PT. Intermittent, erratic behaviour of an implantable cardioverter defibrillator secondary to a hidden magnetic source of interference. Europace 2011; 13:1508. Topic 964 Version 28.0 https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 10/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate GRAPHICS Documented sources of electromagnetic interference (EMI) in patients with implanted cardiac devices Source Examples Electromagnetic fields Daily life* Faulty home appliances Metal detectors Anti-theft equipment Slot machines Cellular phones and accessories with strong magnets (eg, wireless charging, [1] magnetic fasteners) Work and industrial High voltage power lines environment Welding equipment Electronic motors while "on" Induction furnaces Degaussing coils Medical/hospital Magnetic resonance imaging environment Defibrillation or cardioversion Device-device interaction (eg, pacemaker and neural stimulator) Radiofrequency ablation Electrocautery Transcutaneous nerve stimulation Therapeutic diathermy Lithotripsy Radiation therapy There are many potential sources of single-beat inhibition. However, single-beat inhibition is not clinically significant and does not merit specific mention. If working at or near the level of the power line. There is no convincing evidence that being under the power lines at ground level will cause interference. Although all welding equipment is capable of causing interference, it most commonly occurs with equipment that operates at 150 amps. https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 11/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Radiation therapy may cause electromagnetic interference but may also result in direct damage to the pulse generator resulting in sudden no output or "runaway." Reference: 1. Greenberg JC, Altawail MR, Singh G. Life saving therapy inhibition by phones containing magnets. Heart Rhythm; 2021. Reproduced with permission from: Pinski SL, Trohman RG. Interference in implanted cardiac devices, Part I. Pacing Clin Electrophysiol 2002; 25:1367. Copyright 2002 Blackwell Publishing. Graphic 51277 Version 8.0 https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 12/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Implantable cardioverter-defibrillator (ICD) An ICD sits under the skin near a person's heart. Graphic 129613 Version 2.0 https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 13/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Subcutaneous implantable cardioverter-defibrillator Modi ed from: 1. Al-Khatib SM, Friedman P, Ellenbogen KA. De brillators: Selecting the Right Device for the Right Patient. Circulation 2016; 134:1390. 2. Mayo Clinic. Subcutaneous implantable cardioverter-de brillator (S-ICD). https://www.mayoclinic.org/diseases-conditions/ventricular-tachycardia/multimedia/img- 20303862 (Accessed on March 31, 2021). Graphic 130973 Version 1.0 https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 14/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Pacemaker response to magnet placement Pacemaker Magnet mode Explanation manufacturer designation Biotronik AUTO (DEFAULT) If normal conditions, 10 asynchronous events at 90 bpm, then returns to original programmed mode (ie, synchronous pacing) at the lower rate limit. If battery is at ERI, 10 asynchronous events at 80 bpm in VOO mode, then either VDD (dual- chamber) or VVI (single-chamber) with pacing at 11% below the lower rate limit. For any dual- chamber mode, the AVd shortens to 100 milliseconds for the 10 asynchronous events. ASYNCH Asynchronous pacing at 90 bpm if normal conditions. At ERI, 80 bpm (single-step change) in VOO mode regardless of original programming. For any dual-chamber pacing mode, the AVd shortens to 100 milliseconds while the magnet is in place. SYNCH If normal conditions, pacing in original programmed mode, without rate responsiveness. Pacing is at lowest available rate (LRL, sleep rate, or hysteresis rate). If battery is at ERI, then either VDD (dual chamber) or VVI (single chamber) with pacing at 11% below the lower rate limit. Boston Scientific ASYNCH If normal conditions, asynchronous pacing with (includes Guidant Medical CPI) (DEFAULT) 100 millisecond AVd at 100 bpm. If ERI, 85 bpm (single-step change). The Insignia and Altrua models have an intermediate step (90 bpm) at ERN. Most models shorten the pulse width to 50% on the third paced ventricular event (TMT). For Triumph and Prelude models, refer to Medtronic pacemakers, below. OFF No change; magnet is ignored. OFF is also the magnet mode after a "power on reset," or activation of "safety core," which can occur secondary to EMI. EGM mode No change in pacing. Magnet application initiates data collection. Intermedics (purchased by Guidant in 1998, now Boston Scientific, Five asynchronous events at 90 bpm (regardless of battery voltage), then 60 additional asynchronous events at LRL if normal conditions, https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 15/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate but special programmer needed) 90 bpm if ERI, and 80 bpm if EOL. The fifth paced event is emitted at 50% of the originally programmed pulse width (TMT). After the 64th asynchronous event, the magnet is ignored. Medtronic Conventional transvenous pacemakers (including cardiac resynchronization Asynchronous pacing based on programmed mode at 85 bpm if normal conditions*, 65 bpm if at ERI. therapy pacemakers) Leadless intra- cardiac pacemakers (ie, Micra and Micra AV ) No magnet response. MicroPort (Sorin / ELA Medical) Asynchronous pacing at 96 bpm gradually declining to 80 bpm at ERI. Sorin/ELA pacemakers take eight additional pacing cycles (the final two cycles are at LRL with long AVd) upon magnet removal. https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 16/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Abbott (St. Jude Medical "SJM" radiograph Battery test (DEFAULT) Asynchronous pacing at 100 bpm (older models 98.6 bpm) gradually decreasing to 85 bpm (older [SJM], Pacesetter) logo; standard transvenous pacemaker models 86.3) at ERI. OFF No magnet response. Event snapshots No change in pacing. Magnet application causes pacemaker to collect data. Identity and Entity models lack this feature. Event snapshots + battery test For a magnet placed on the device for two seconds, pacing mode and rate are unchanged, and the device stores an electrogram. If the magnet is placed for =5 seconds, the battery test mode (refer to above) is activated. Identity and Entity models lack this feature. Pacesetter radiograph Battery test (DEFAULT) Asynchronous pacing, and the rate depends upon specific model. In general, a pacing rate of less logo; standard transvenous pacemaker than 90 bpm should prompt further evaluation. OFF No magnet response. VARIO mode VARIO results in a series of 32 asynchronous (present in some models) pacing events. The rate of the first 16 paces reflects battery voltage, gradually declining from 100 bpm to 85 bpm at ERI. The next 15 paces are used to document ventricular pacing capture safety margin. The rate will be 119 bpm with gradually declining pacing voltage. The 16th pace of this group is at no output. The next pace restarts the 32-event sequence. The 32-event sequence repeats while the magnet remains in place. "Nanostim" leadless intra-cardiac pacemaker On (DEFAULT) Asynchronous pacing at 100 bpm for eight cycles, then 90 bpm if normal conditions; 65 bpm if ERI. OFF No magnet response. The effect(s) of appropriately placing a magnet over a pacemaker are shown, assuming normal battery and lead function. Column 1 shows the pacemaker manufacturer. Where a manufacturer has multiple responses, Column 1 is subdivided. If the magnet response is programmable, then Column 2 shows the various magnet modes available. The first mode shown is the default. A device reset from EMI might produce some other mode (ie, magnet mode disabled). Column 3 shows the effect on pacing therapy for the magnet mode shown in Column 2. Unless otherwise specified, asynchronous pacing takes place, without rate responsiveness, in the chambers originally programmed. Thus, a dual-chamber program would result in DOO pacing; a single-chamber program would result in VOO (unless an atrial device, which would be AOO) pacing; and a biventricular, dual- chamber device would be DOOOV. https://www.uptodate.com/contents/cardiac-implantable-electronic-device-interactions-with-electromagnetic-fields-in-the-nonhospital-environment/print 17/20 7/6/23, 10:47 AM Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment - UpToDate Caution for Medtronic transvenous pacemakers: All Medtronic transvenous pacemakers except Enrhythm P1501, EMDR series, Revo, Advisa, and Ensura suspend magnet detection for up to 60 minutes following removal of the programming head after an interrogation session, unless specific programming action (which requires multiple "button" depressions) is taken prior to removing the programming head. Caution for all dual-chamber pacemakers: An electrical fault or exposure to strong EMI could cause a "power on reset" or "safety core event" (BSC - Boston-labeled devices), causing the pacemaker to switch to VVI pacing only, regardless of prior pacing programming. For a dual-chamber pacemaker with a bad RV lead and programmed to atrial pacing only (AAI, AOO) in a pacing-dependent patient, this event could result in patient injury or death. For further explanation of terms, refer to UpToDate topics on modes of cardiac pacing and cardiac pacing nomenclature. bpm: beats/minute; ERI: elective replacement indicator (the device should be replaced promptly - the US Food and Drug Administration [FDA] requires pacemakers to perform safely for at least three months from onset of ERI); VOO: ventricular asynchronous pacing, no sensing; VDD: ventricle paced, atrium and ventricle sensed, and either inhibition or tracking of the pacemaker in response to a sensed beat; VVI: ventricle paced, ventricle sensed, and pacemaker inhibited in response to a sensed beat; AVd: atrioventricular delay (for dual-chamber pacing; note that this is a programmed value, although the AVd can be shortened during the first 3 to 15 events upon magnet placement; note that a short AVd can reduce stroke volume and produce untoward hemodynamics in some patients); LRL: lower rate limit (the programmed lower rate, or set point, of the pacemaker); ERN: elective replacement near (the device should be undergoing monthly checks [IFI]); TMT: threshold margin test (This is the emission of a single pacing pulse [except VARIO - refer to St. Jude Medical Pacesetter Logo] at a lower amplitude or pulse width to demonstrate adequacy of pacing output relative to pacing threshold. Typically, this is the third or fifth pacing pulse, and failure to capture [pace] on this event suggests an inadequate safety margin for capture. Properly programmed atrial- only pacemakers are unlikely to demonstrate this feature.); EMI: electromagnetic interference; EGM: electrogram; EOL: end of life (the device should be replaced immediately); AOO: asynchronous A pacing; AAI: atrium paced, atrium sensed, and pacemaker inhibited in response to sensed atrial beat; ERT: elective replacement time (Same as ERI for Boston Scientific pacemakers [Guidant, CPI labels also]. At ERT, rate-responsive programming is cancelled. At three months post-ERT, only single- chamber operation continues.); SSI: single-chamber, inhibited mode (If implanted for ventricular pacing, then SSI = VVI. For an atrial pacemaker, SSI = AAI.). Some Medtronic pacemakers deliver the first three or five asynchronous beats in magnet operation at 100 bpm. The first three asynchronous paces of the Adapta, Versa, Sensia, and Relia models are at 100 bpm (the amplitude of the last of the three 100 bpm paced beats is reduced by 20%). The first