In poker, you learn to keep your cards close to your chest not to reveal your hand, but if you’re thinking electronics, that’s not a good idea. In fact, Apple has issued a warning to users who have certain medical devices to use caution when holding and handling their phones and other products that contain magnets or other components that emit electromagnetic fields.

According to The Sun, keeping your iPhone and other products in proximity to your chest  can interfere with medical devices such as implanted pacemakers and defibrillators. The sensors of these devices may respond to magnets and radios of electronics when in close contact, says Apple.

To avoid any potential interactions with these devices, Apple suggests keeping your product at a safe distance. This means more than six inches away from your implanted device, or more than 12 inches when charging. Apple recommends checking with your doctor about your specific situation to get updated guidelines. If you feel your Apple product is interfering with your device, stop using it.

Besides iPhones and MagSafe accessories, the tech giant says iPads and their accessories, AirPods and cases, HomePods, MacBooks, and Beats contain magnets that could interfere with medical devices.

Here is a complete list of Apple products that contain magnets and should be kept at a safe distance from your medical device. Apple noted that some other products contain magnets as well, says The Sun, but are unlikely to interfere with medical devices.

The notice from Apple coincides with previous medical studies by the Journal of the American Heart Association (JAHA) and the Heart Rhythm Journal (HRJ) that concluded the iPhone 12 range “has the potential to inhibit lifesaving therapy.”

According to Forbes, JAHA stated, “People often put their smartphones in a breast pocket over a device which can be in close proximity to CIEDs (cardiac implantable electronic devices). This can lead to asynchronous pacing or disabling of anti-tachycardic therapies.”

While Apple products were tested, experts, such as the American Heart Association, recommend that people with implanted devices keep all cellphones and electronic devices, which could also contain strong magnets, a safe distance away.