Static magnetic field measurements of smart phones and watches and applicability to triggering magnet modes in implantable pacemakers and implantable cardioverter-defibrillators

Abstract

Overview

Implantable pacemakers and implantable cardioverter-defibrillators (ICDs) contain a 'magnet mode' which is crucial during procedures with possible electromagnetic interference. Recent studies, notably in Heart Rhythm, highlighted how consumer electronics like the iPhone 12 can unintentionally activate this mode.

Objective

This research aims to identify the separation distances at which consumer electronic devices such as cell phones and smart watches might trigger the magnet mode in pacemakers and ICDs.

Methods

Measurements were conducted using an FW Bell 5180 Gauss Meter and STD18-0404 Transverse probe. Devices tested include iPhone 12 models and Apple Watch 6.

Findings

• All devices tested had fields above 10 G at close range (1-11 mm).
• The magnetic field strength drops below 10 G between 11 and 20 mm.

Conclusion

It is recommended, supporting the FDA's guidelines, that devices potentially causing magnetic interference such as smartphones and watches be kept at least 6 inches away from pacemakers and defibrillators to avoid unintended activation of magnet mode and associated health risks.