UPDATE: March 1, 2022: Consumer electronic devices such as the Apple AirPods Pro charging case, Apple Pencil 2nd Generation and Microsoft Surface Pen can interfere with the function of implanted cardioverter defibrillators, according to a new Swiss study.

While the study assessed ICDs that were not implanted in patients, researchers warned patients with implants to keep such electronic devices at least one inch from their chest to prevent dangerous magnetic interactions.

In the study, published today in the journal Circulation: Arrhythmia and Electrophysiology, the Apple and Microsoft devices were placed increasingly closer to five defibrillators from "two representative manufacturers" until deactivation occurred.

Researchers found that around 2 cm (0.78 inches) away for the Apple products and 2.9 cm (1.14 inches) away for the Microsoft device were their respective deactivation points.

“If you carry a portable electronic device close to your chest and have a history of tachycardia (rapid heartbeat) with an ICD, strong magnets in these devices could disable your cardioverter defibrillator,” said lead author Corentin Féry, a research engineer at the University of Applied Sciences and Arts Northwestern Switzerland, Institute for Medical Engineering and Informatics.

The study comes about a year after Apple and the FDA warned the public that magnets in the iPhone 12 and other products might interfere with pacemakers, defibrillators and other implanted medical devices. 

"What is most concerning is that magnets are being used in more and more portable electronic devices, and with so many magnets around us, the risk to cardiac patients is even greater," said study co-author Sven Knecht, a research engineer at the Cardiovascular Research Institute at University Hospital Basel.

Dive Brief:

• FDA has issued a public warning that high-strength magnets in some cell phones and smartwatches used by consumers can potentially affect the proper functioning of pacemakers and other implanted medical devices. Still, it said the risk to patients is low.
• The agency said recent studies have shown that such consumer electronic products may cause certain devices to switch to "magnet mode" and suspend normal operations. As a result, cardiac defibrillators may be unable to detect tachycardia events in which a patient's heart rate is over 100 beats per minute.  
• FDA recommended patients keep cell phones and smartwatches that may create magnetic interference at least six inches away from implanted medical devices, particularly cardiac defibrillators. Apple in late March published its own warning to customers that magnets in the iPhone 12 and other products might interfere with implanted pacemakers and defibrillators.    

Dive Insight:

Implanted cardiac defibrillators are designed to detect an irregular heartbeat and shock the heart back into a normal rhythm. FDA on Thursday warned that when such a device stops working patients "may experience dizziness, loss of consciousness or even death if therapy is not delivered when lifesaving shocks are required."

High-strength magnets can also cause pacemakers to deliver electrical impulses that make the heart beat out of sync, which can result in a potentially lethal condition called ventricular fibrillation.

FDA said it is not aware of any adverse events associated with the magnet issue currently, but is continuing to "monitor all relevant scientific information" and will take further action "if the need arises based on its risk analysis."

More than 300,000 people in the U.S. undergo surgery to implant such devices annually. 

Jeff Shuren, director of the FDA's Center for Devices and Radiological Health, in a written statement said "the number of consumer electronics with strong magnets is expected to increase" and recommended patients with implanted devices "talk with their healthcare provider to ensure they understand this potential risk and the proper techniques for safe use."  

Implanted medical devices are designed with a "magnet mode" that allows for safe operation during certain medical procedures such as MRI scans. However, the agency warned that high-strength magnets in cell phones and smartwatches may cause certain devices to switch to this magnetic safety mode suspending their normal operations until the magnet is moved away. 

FDA conducted its own testing on some consumer electronic products that use high-strength magnets and confirmed the findings of recent studies showing that they may cause certain devices to turn on the magnetic safety mode of the medical devices.

Cardiologists at the Henry Ford Heart and Vascular Institute specifically wrote about the problem as it relates to the iPhone 12 in a January letter to the editor of the medical journal HeartRhythm. In their study, they tested the iPhone's interaction with a patient's Medtronic implantable cardioverter-defibrillator and found "immediate suspension" of ICD therapies. 

The authors called it "an important public health issue concerning the newer-generation iPhone 12, which potentially can inhibit lifesaving therapy in a patient, particularly when the phone is carried in an upper chest pocket." The cardiologists said medical device makers and physicians must "remain vigilant" about the potential problem.