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Experts say devices such as iPhones should be held a safe distance from pacemakers. MoMo Productions/Getty Images
  • Some doctors have issued a warning, saying the new iPhone 12 series contain stronger magnets that could disrupt the functioning of pacemakers and implantable cardioverter-defibrillators (ICDs).
  • They say the warning also can apply to other devices such as iPods or MP3 players if held too close to pacemakers or ICDs.
  • They recommend that electronic devices not be stored in shirt pockets, over-the-shoulder bags, or other items close to a person’s heart.

The release of Apple’s newest technology — the iPhone 12 series — is reviving old concerns about the safety of cellphones and people with pacemakers and implantable cardioverter-defibrillators (ICDs).

The cause for pause comes from the smart technology’s addition of a circular array of more powerful magnets around a central charging coil that makes the phone compatible with MagSafe accessories such as cases, wallets, and wireless chargers.

Doctors say carrying the device in a shirt pocket, bra, chest mount, or wraparound purse could suspend your pacemaker and ICD’s ability to send high-voltage shock therapy when needed.

Doctors cite concerns over what they’re calling an “important public health issue” regarding the newer-generation iPhone 12 in a letter to the editor in Heart Rhythm.

They tested the safety of the device on a person with an ICD and found that once the iPhone was brought close to the ICD over the left chest area, an immediate suspension of ICD therapies occurred and persisted for the duration of the test.

“This result was reproduced multiple times with different positions of the phone over the pocket,” states the letter.

The doctors further cite a report from 2020 showing magnetic interference from a fitness tracker wristband that deactivated an ICD up to distances of 2.4 centimeters (cm).

They say this suggests other popular smart technologies used for lifestyle and health management pose similar potential for problems in people with pacemakers and ICDs.

The American Heart Association has long since advised people with ICDs to be aware of their surroundings and that devices with strong magnetic fields can disrupt their functioning.

This is also common knowledge in the medical community.

“Patients with pacemakers and ICDs have long been given instructions about the use of cellphones and their devices,” says Dr. Bruce L. Wilkoff, the director of cardiac pacing and tachyarrhythmia devices and a professor of medicine at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University in Ohio.

These standard instructions included not keeping cellphones (or iPods/MP3 players) in front pockets and avoiding holding them against the ear on the same side as the ICD.

Wilkoff echoes it isn’t only the iPhone 12 or even cellphones that should be used with caution.

“While this research points out that there are magnets in this particular cellphone, staying away from this and other devices with magnets is important in that they will modify both pacemaker and ICD function during the time of close contact,” he told Healthline.

“Other reports have also pointed out that the clasps in watches and step counters also have magnets and it is important to not let them rest over pacemakers and ICDs,” he added.

The new magnets are more powerful and this does heighten their potential to disrupt device functioning.

But the problem isn’t — and never has been — with the magnets themselves.

“Even phones without magnets can affect the function of the pacemaker or ICD when the phone is in proximity to the device,” Wilkoff said. “The problem is the proximity of the magnet, which is intended to affect the function of the pacemaker and ICD when in proximity.”

“The magnets are not dangerous to the pacemaker or ICD as we use magnets as a normal part of adjusting the devices,” he explained.

“The effect of a magnet on a pacemaker is usually to temporarily turn on the pacing function and to ignore the signals from the heart. The effect of a magnet on an ICD is usually to temporarily disable the ICD response to the rapid heart rhythms that is necessary to save the patient’s life,” said Wilkoff.

“The response is restored by removing the magnet from close contact (about 3 to 5 inches),” he noted.

Whether you upgrade your phone or not, Wilkoff recommends taking safety precautions to ensure proper ICD functioning.

“Developing these habits will be good for this and any new phone that they get,” he said.

Wilkoff’s tips include:

  • keeping your phone in some other place than in a pocket over the pacemaker or ICD
  • making a habit of using the opposite ear for calls

However, you don’t need to panic if you forget.

“Using the same ear is likely too far to affect a change in the device function,” Wilkoff said. “The likelihood of a problem is very small with accidental co-location of the phone and pacemaker or ICD.”

Apple suggests keeping your iPhone and MagSafe accessories a safe distance away from your device (more than 6 inches/15 cm apart or more than 12 inches/30 cm apart if wirelessly charging) to avoid any potential interactions with these devices.

They also recommend talking to your doctor for specific guidelines.