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Smartphones and your heart

Last Modified: March 05, 2021

Heart Health

smartphone and heart

Apple released a statement earlier this month stating a recent study found that the newest smartphone models contain powerful magnets that can potentially affect pacemaker and defibrillator function. To help answer our questions, we turned to David Schleinkofer, MD, PPG – Cardiology, for more on this widespread health concern.

How are the sensors in pacemakers and defibrillators sensitive to cellphones magnets?

Both pacemakers and defibrillators have a reed switch component that is sensitive to magnets and used in specific testing modes.

Can cell phone magnets prevent a lifesaving shock?

The magnets in a cell phone create a different response for a pacemaker versus a defibrillator. Let’s explore the different reactions between the two devices:

  • A pacemaker: If exposed to a magnetic field, a pacemaker does a battery test, which will increase the patient's heart rate. A typical heart rate for a pacemaker patient is 60 beats a minute. When a magnet is applied, their heart rate increases to 85 or 90 beats a minute, depending on the manufacturer.
  • A defibrillator: With a defibrillator, the magnet does not change the heart rate. Instead, it renders the device blind, so it no longer detects any heart arrhythmias and will not deliver a shock. In other words, when applied to the defibrillator, if the patient were to have a life-threatening arrhythmia, it would not treat it until you remove the magnet. With that said, certain situations call for the patient's device to be blind. For example, if doctors use electric cautery during surgery, they would want to blind the device so it wouldn't respond during the procedure.   
Have you had any patients come to you with concerns?

We have had several calls, but the positive is that the manufacturers already recognized this issue, so most defibrillator companies have installed an auditory tone in their devices, and if exposed to a magnetic field, it will warn the patient, giving them a chance to move away from the magnet.

Older devices that don't have the auditory tone create what's called a time-date stamp. The next time our clinic interrogates the device, we can see if they were exposed to a magnetic field and discuss the occurrence with them.

What safety precautions would you recommend for patients who already have the phone?

First, we ask patients not to carry the cell phone in their shirt pocket, especially if they have a left-sided device. This is because the phone's physical weight pushes against the pacemaker or defibrillator and could cause interference due to proximity. Instead, we suggest carrying the phone in your pants pocket, a holster on your hip or setting it on your bedside table where it won't interact. However, if you're lying down or lying on the device, there's a greater chance of interference. Additionally, if you're already lying down, you may not notice symptoms of a heart rhythm problem. Whereas if you are standing, you're more likely to notice the warning signs.

Are individuals more at risk if they are using their phones while charging them at the same time?

Honestly, if you're using a wireless charger for your cell phone, that could create an electric field that could potentially interfere with your cardiac device. However, the distance or your proximity is important to note. For example, if you're more than six inches away, your risk is virtually zero when your phone is charging. It would be challenging to wirelessly charge your phone while having your chest close enough to cause an issue.

Do you think this will be an ongoing problem as we continue to make technological advances?

Believe it or not, this is both a new and an old problem. When cell phones first became available, they were all analog phones with antennas that would extend. This phone type actually created more interference with devices than we have now with current digital cell phones. However, we are now seeing a resurgence of interference due to the magnetic fields used for wireless charging.

Will current devices need to be adjusted?

No, because manufacturers know about the magnet issue. They include audible alerts in devices to notify patients. So, someone must go out of their way to create a situation where there will be interference. As previously mentioned, the phone must be resting on the cardiac device to cause an issue.

Final thoughts

Remember, we have not seen any meaningful interactions between phones and devices. Many pacemakers and defibrillators are also ready to alert an audible tone if exposed to a magnet, thus warning patients. Nevertheless, if you are unsure or have questions, please consult your physician regarding your specific case and cardiac device.

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