Magnetic interference from consumer devices: a renewed challenge for the safety of cardiac implantable electronic devices

This editorial refers to ‘Preventing smartphone induction of magnet mode in cardiac implantable electronic devices’ by F.K. Wegner et al., https://doi.org/10.1093/europace/euaf170.

The interaction between cardiac implantable electronic devices (CIEDs), such as pacemakers (PMs) and implantable cardioverter defibrillators (ICDs), and external sources of electric, magnetic, and electromagnetic (EM) fields has been an area of clinical interest and scientific investigation for decades.^1–3 These life-sustaining devices are designed to operate reliably within a world that is increasingly saturated with EM signals from a multitude of sources. Over the years, the proliferation of EM-emitting technologies, ranging from radio frequency identification (RFID) systems and physiotherapy equipment to Bluetooth, Wi-Fi, and more recently induction cooktops and wireless charging, has created an ever-evolving landscape of potential interference sources.

The exponential growth in portable electronics, especially consumer-grade devices, has expanded the range of potential interference sources. Technologies once restricted to clinical or industrial use have now become integral to everyday life. The RFID systems are now ubiquitous in access control and inventory management; physiotherapeutic equipment is commonly used in both clinical and home settings; and communication protocols like Bluetooth and Wi-Fi are ever-present. These innovations offer remarkable convenience but introduce new vectors for unintended interaction with medical implants.^4–6

In parallel, regulatory and standards organizations overseeing CIED safety have worked to address new and emerging EM sources by updating the framework for EM compatibility requirements.⁷ These regulations aim to ensure patient safety by defining specific testing that addresses emerging sources of interference and by recommending exposure guidelines. Manufacturers conduct standardized tests to ensure device immunity under defined exposure conditions. Nevertheless, the dynamic and rapidly evolving nature of consumer technology presents challenges that may not be fully addressed by existing protocols. One area that has gained recent attention is wireless charging systems, particularly those that utilize magnets to align the transmitting and receiving coils for efficient energy transfer.

Wireless charging systems have been adopted widely, notably in smartphones and wearable devices, which increasingly rely on magnetic coupling to facilitate efficient charging. This necessitates the use of permanent magnets, such as those found in the Apple iPhone’s MagSafe system, to align the transmitter and receiver coils during charging. While effective from a technological standpoint, these magnetic fields pose potential risks to patients with CIEDs.

This issue arises from the intentional design of CIEDs to respond to magnetic fields. As counterintuitive as it may seem, these devices are engineered to be highly immune to electric and EM fields, while remaining deliberately sensitive to magnetic fields stronger than 1 mT.

This design choice originates from the need to enable a specific device configuration that can be used in particular situations and strictly under medical supervision, such as during device programming, surgical procedures, or emergency deactivation. When activated, this setting typically causes PMs to operate in asynchronous mode (i.e. pacing without sensing intrinsic cardiac activity) and defibrillators to temporarily disable shock therapy.

Because this configuration carries inherent risks and must be activated externally only by healthcare professionals in tightly controlled environments like hospitals or clinical facilities, the most appropriate solution was to use a specific magnet as an intentional external activation tool. In fact, CIEDs have long incorporated a ‘magnet mode’ (also known as a mode switch), which temporarily enables this special setting when a magnet, specifically supplied by the device manufacturer, is deliberately placed over the device.

Originally, it was assumed that accidental exposure to magnetic fields stronger than 1 mT in everyday life would be extremely unlikely. However, this assumption has been challenged by the advent of magnetic alignment systems used in wireless charging technologies, such as Apple’s MagSafe for the iPhone. The magnetic field strength generated by these systems can unintentionally trigger magnet mode in CIEDs when the phone is placed near the implant site, particularly in certain positions or conditions, such as being carried in a shirt pocket or resting on the chest during sleep.

While such occurrences are rare, they present a potential safety concern that deserves careful consideration and awareness.

In this regard, it should be noted that both CIED and phone manufacturers provide recommendations concerning the potential interactions between these devices. They advise maintaining a distance of 15 cm between the phone and the implant and 30 cm when the phone is charging wirelessly. Other recommendations include holding the phone to the ear on the side opposite the implant and avoiding carrying the phone in a breast pocket. However, these recommendations are often not well known and are therefore frequently ignored by users. It is thus necessary to increase awareness on this topic by promoting research that can clarify the associated risks and provide possible solutions.

Recent publications have brought this issue to light, exploring the extent and mechanisms of interference through a range of experimental setups.^8–10 The recently published article in Europace¹¹ makes a notable contribution to this area of research. It not only confirms the potential for magnetic interference between the iPhone MagSafe system and various CIEDs but also proposes practical solutions to mitigate the risk. Specifically, the authors demonstrate that magnetic shielding with a thin steel plate or submuscular CIED placement prevents interaction with the ICD or PM.

This study represents an excellent example of how applied research can illuminate previously underappreciated risks and offer viable solutions. It underscores the need for vigilance and adaptability in both medical and technological fields. By highlighting the mechanisms of interference and offering concrete mitigation strategies, this work not only advances the state of knowledge but also empowers clinicians and patients alike.

Such technical solutions, while promising, also serve a broader purpose: raising awareness. Clinicians must be informed of the possibility of such interactions so they can advise their patients appropriately. Patients, in turn, need clear, comprehensible guidance on how to use their consumer devices safely. While the overall incidence of interference may be low, the consequences of inappropriate device behaviour can be life-threatening. Even a single inappropriate shock from an ICD due to interference, or the failure to deliver a necessary shock because of ICD inhibition, may pose an unacceptable risk. Similarly, inducing a ventricular tachyarrhythmia through asynchronous pacing during the ventricular vulnerable period as weel as failing to pace in a PM-dependent patient are serious events that must be absolutely prevented.

From a broader perspective, this issue highlights the importance of post-market surveillance and real-world evidence in medical device safety. While premarket testing is rigorous, it cannot anticipate every interaction in the diverse and unpredictable contexts in which patients live. Continued observation, reporting, and investigation of adverse interactions will be key to maintaining the high standards of safety to be expected from modern medical devices.

A key challenge lies in balancing innovation with patient safety. Consumer electronics manufacturers generally do not consider medical implants when designing their products. Similarly, medical device manufacturers cannot foresee every new technological trend that might emerge. Bridging this gap will require ongoing collaboration among technologists, engineers, physicians, and regulatory bodies. It is important that basic knowledge and continuing medical education for physicians and allied professionals involved in the practice of cardiac electrophysiology specifically include the basis for prevention, diagnosis, and treatment of CIED troubleshooting due to any type of interference, including consumer devices.¹²

Moreover, public education plays a vital role. The scientific community can help for the dissemination of this knowledge beyond academic journals and into the hands of patients, caregivers, and primary healthcare providers. The dissemination of accurate, actionable information about the safe use of technology is essential.

In conclusion, the intersection of consumer electronics and implantable cardiac devices is a dynamic and growing field that demands careful attention. Research efforts like the one highlighted in this issue of Europace provide critical insights that can shape clinical practice, inform regulatory policy, and ultimately protect patients. As technology continues to evolve, strategies for ensuring the safe coexistence of medical and consumer devices in today’s world must also evolve.

Funding

No fundings have been used.

Data availability

Data availability does not apply since this is an editorial.