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It’s been known for some years that Cardiac Implantable Electronic Devices (CIEDs) such as pacemakers and defibrillators, designed to regulate and monitor the heart’s electrical activity, may be affected by electromagnetic interference (EMI) from various sources. Modern medical devices are generally designed to be resilient to many types of EMI. However, as the use of new technology, such as electric cars and inductive cooktops, becomes more widespread, it is important that providers continue to evaluate and understand the possible risks these technolgies present for patients with CIEDs.
All providers, both cardiology and non-cardiolgy, should be aware of the impact of these technological advances when caring for patients with CIEDs. Below are some points to consider regarding the potential impact of this technology on the implantable devices.
Electric Cars and Magnetic Fields: Electric cars generate magnetic fields due to large electric motors and high-voltage systems. While the magnetic fields produced by electric vehicles are relatively weak, there is a potential for interaction with implantable devices. However, most pacemakers and defibrillators are designed to be shielded against such magnetic fields.
In a recent issue of the Annals of Internal Medicine, Lennerz et al. assessed EMI in a series of 108 patients with CIEDs using four popular electric car models (BMW i3, Nissan Leaf, Tesla Model 85S, and Volkswagen e-up!) in an observational study. Electromagnetic field testing was performed in 3 phases: 1) around the car as the participants sat in the front seat of the car while on a roller test bench, 2) during car charging, and 3) inside the car as the investigators drove the participants on the road. EMI was assessed by cardiologists blinded to electrocardiograms and device monitors.
The authors report that despite the electrocardiograms showing the presence of EMI, there was no evidence of EMI with CIEDs. There were no episodes of inappropriate device function and no changes in the post-exposure sensing, threshold, or impedance parameters. The authors concluded that the shielding for the onboard computers in these electric cars may have been the reason for the low electromagnetic field observed inside the vehicles and the lack of EMI with the CIED.2
EMI From Consumer Products: Besides electric cars, other electric-powered consumer products can emit electromagnetic radiation that may interfere with the operation of implantable devices. Although EMI can potentially affect the functioning of pacemakers, defibrillators, and loop recorders, possibly causing temporary malfunctions or inappropriate therapy delivery, rigorous safety standards and testing protocols are in place at most of the major manufacturers to ensure the electromagnetic compatibility of these CIEDs. Shielding techniques, advanced circuitry, and continuous updating of the implantable devices minimize the risk of interference from many everyday external sources.
Cell phones and similar electronic devices: A 2022 study found that recent generations of smartphones appear to have no EMI effect on CIEDs and can be used safely with less concern about adverse events, including pacemaker inhibition, inappropriate ICD shock, and CIEDs device malfunction.3 However, the increasing use of magnets in consumer electronics for wireless charging and other functions has created additional concerns. Newer generation smartphones, smartwatches and wireless headphones have demonstrated the capability to cause reversion to magnet mode in CIEDs.4 Patient should be instructed to keep smartphones and associated accessories at least 6 inches away from the CIED to avoid this risk. A similar risk of magnet reversion has been identified in CPAP masks that use magnetic clips; current recommendations are to avoid the use of these masks in patients with sleep apnea who also have a CIED. 5, 6
Security Systems and Metal Detectors: Some security systems and metal detectors use electromagnetic fields that can potentially interfere with CIEDs causing over-sensing, asynchronous pacing, and inappropriate shocks. It’s essential to inform security personnel about the presence of a CIED and follow their instructions for passing through these devices. The current recommendation is that patients with a CIED can safely go through a walk-through metal detector or wand testing, such as those found at most airports, with minimal risk of EMI, although the alarm may trigger due to exposure to the pulse generator of 200 to 400 Hz. 7
Distance and Proximity: Maintaining a safe distance between an implantable device and potential sources of EMI is always advisable. However, some consumer products are more troublesome than others for those with CIEDs. One such product that has come into question of late is the introduction of induction stoves in many households. In induction cooktops, coils produce varying magnetic fields that induce localized electric currents in the ferromagnetic materials at the bottom of a pot or pan, thereby heating it while keeping the cooktop cool. There could be interference with pacemaker sensing produced by voltages induced directly by induction or indirectly by leakage currents.8 As a precaution, and until more research is done, it is recommended that people with a CIED, particularly a pacemaker, maintain a minimum distance of approximately 2 feet between the device and the induction stovetop.
Precautions and Consultation: Patients with implantable devices should always consult with their healthcare providers about potential risks and precautions regarding any exposure to sources of EMI. Healthcare professionals can provide specific guidance based on the individual patient’s device, length of exposure and proximity to the EMI, age, and overall medical condition.
It’s important to note that manufacturers of CIEDs have responded to this growing challenge of patient exposure to EMIs with improved device protection from unwanted effects, such as the use of titanium cases, special circuitry designed to filter out signals from EMI sources with commonly used frequencies, and specialized algorithms designed to distinguish between noise and true intracardiac signals. Many implanting physicians also use bipolar leads more frequently than unipolar leads, minimizing the “antenna” effect and, thus, the propensity toward a device sensing unwanted electrical signals.9 It’s worth mentioning that medical technology and safety standards are continually advancing, and manufacturers are consistently working to improve the resistance of all implantable devices to various forms of interference, including EMI from electric cars, consumer electronic devices, and other electronic products.
1 https://www.jacc.org/doi/10.1016/j.jacc.2018.09.090
2 https://www.jacc.org/doi/10.1016/j.jacc.2018.09.090#bib5
3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9535763/
4 https://link.springer.com/article/10.1007/s11886-022-01653-0
5 https://www.jacc.org/doi/10.1016/S0735-1097%2819%2931105-2
6 https://jcsm.aasm.org/doi/10.5664/jcsm.10478
7 https://www.jacc.org/doi/10.1016/j.jacc.2018.09.090
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Cardiac RMS LLC is a clinical service partner with expertise in remote monitoring of patients who have a cardiac pacemaker, implantable cardiac defibrillator, implantable heart failure device, or implantable loop recorder. Services also include Virtual Care Management, utilizing Remote Physiologic Monitoring (RPM) and care management to remotely support the treatment of patients with chronic conditions.
