FDA Data Confirm Smartphone Interference With Cardiac Devices

Megan Brooks

August 26, 2021

A new study by scientists at the US Food and Drug Administration (FDA) supports the agency's standing recommendation to keep consumer electronic devices, such smartphones and watches, at least 6 inches away from implanted medical devices, especially pacemakers and defibrillators, to avoid potential interference.

Implanted pacemakers and cardioverter-defibrillators (ICDs) include a "magnet mode" feature that can be activated by magnets stronger than 10 G.

This feature is helpful when a patient is undergoing a procedure where electromagnetic interference is possible, or anytime suspension of tachycardia detection and therapy is needed.

But research has shown that high field strength magnets in newer smartphones may cause some implanted medical devices to switch to magnet mode and suspend normal lifesaving operations until the magnet is moved away.

As a result, last spring the FDA advised patients and caregivers to keep smartphones and watches at least 6 inches away from implanted medical devices, such as pacemakers and defibrillators, as reported by theheart.org | Medscape Cardiology. 

To investigate further, FDA scientists, led by Seth J. Seidman, with the Center for Devices and Radiological Health (CDRH), tested the magnetic field output of all iPhone 12 and Apple Watch 6 models at varying distances from the devices.

They found that all the devices have static magnetic fields significantly greater than 10 G in close proximity, high enough to place implanted cardiac devices into magnet mode.

However, when a separation distance of 6 inches or more is maintained, the phones and watches will not trigger magnet mode.

The study was published online August 26 in Heart Rhythm.

"Ensuring the safety of our nation's medical devices is a cornerstone of our consumer protection mission, especially as technology continues to advance," Seidman said in a news release.

"Because of these results, we are taking steps to provide information for patients and healthcare providers to ensure they are aware of potential risks and can take simple proactive and preventive measures like keeping consumer electronics, such as certain cell phones and smartwatches, 6 inches away from implanted medical devices and not carrying consumer electronics in a pocket over the medical device," Seidman added.

Asked for comment, an FDA spokesperson told theheart.org | Medscape Cardiology that, "The FDA continues to monitor all relevant scientific information about this ongoing issue and will continue to take appropriate action, including informing the public and providing additional information, if the need arises based on its risk analysis." 

The study had no specific funding. The authors have declared no relevant financial relationships.

Heart Rhythm. Published online August 26, 2021. Full text

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