Medical experts are warning that the magnetic charging technology in the iPhone 12 could pose a danger to your heart.

The MagSafe technology allows for wireless charging and for easier accessory attachment.

Three cardiologists from Henry Ford Heart and Vascular Institute wrote about the issue in the medical publication Heart Rhythm Journal.

They said iPhones can interfere with implantable cardioverter-defibrillator devices. Doctors were concerned the strong magnetic array in the iPhone could cause an issue, so they tested it out on a patient with an implanted device.

According to the article, “Once the iPhone was brought close to the ICD over the left chest area, immediate suspension of ICD therapies was noted and persisted for the duration of the test.”

This was not a one-time occurrence, “This result was reproduced multiple times with different positions of the phone over the pocket.”

They warned patients with implanted devices against carrying iPhones in their shirt pockets.