Static Magnetic Field Measurements in Smartphones and Watches, and Applicability to Magnetic Mode Triggering of Implantable Pacemakers and Implantable Defibrillators

Publication date: August 25, 2021 DOI: https : //doi.org/10.1016/j.hrthm.2021.06.1203

Commentary

Implantable pacemakers and implantable cardioverter defibrillators (ICDs) appear to be designed to include a "magnet mode" feature that can be activated from magnets greater than 10 G. This feature is designed to be used when the patient is undergoing a procedure that has the potential for electromagnetic interference, according to the report.

The purpose of this study was to determine the separation distance between cell phones and smartwatches with household appliances that could cause magnetic interference and implantable pacemakers, or ICDs, that can trigger magnetic modes.

The static magnetic fields of the iPhone12 and AppleWatch were measured in several planes with a resolution of 1 cm using a FW Bell 5180 Gaussmeter equipped with an STD18-0404 transverse probe (unidirectional probe). The results show that all iPhone12 and AppleWatch 6 models tested have static magnetic fields well in excess of 10 G at close proximity (1-11 mm) and decay to less than 10 G between 11 and 20 mm.

This supports the idea that these digital devices can cause magnetic interference and should be kept at least 6 inches away from pacemakers and cardiac defibrillators.