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

2021 · Harm · Low evidence

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HarmLow evidencePaper 1011

Measured static magnetic fields from iPhone 12 models and Apple Watch 6 were reported to be >10 G at close proximity (1–11 mm) and to attenuate to <10 G between 11 and 20 mm. The authors conclude this supports FDA advice to keep such consumer devices at least…

Study snapshot

Publicationmanual · 2021

Study typeexposure_assessment

Reported directionHarm

Evidence ratingLow

Abstract

Static magnetic field measurements of smart phones and watches and applicability to triggering magnet modes in implantable pacemakers and implantable cardioverter-defibrillators Seth J Seidman, Joshua Guag, Brian Beard, Zane Arp. Static magnetic field measurements of smart phones and watches and applicability to triggering magnet modes in implantable pacemakers and implantable cardioverter- defibrillators. Heart Rhythm. 2021 Oct;18(10):1741-1744. doi: 10.1016/j.hrthm.2021.06.1203. Abstract Background: Implantable pacemakers and implantable cardioverter-defibrillators (ICDs) are designed to include a "magnet mode" feature that can be activated from magnets stronger than 10 G. This feature is designed to be used when a patient is undergoing a procedure where electromagnetic interference is possible, or anytime suspension of tachycardia detection and therapy is needed. A publication in Heart Rhythm demonstrates an iPhone 12 triggering the magnet mode of a Medtronic ICD. Objective: The purpose of this study is to determine the separation distance between consumer electronic devices that may create magnetic interference, including cell phones and smart watches, and implantable pacemakers and ICDs where magnet mode can be triggered. Methods: The static magnetic fields of the iPhone 12 models and Apple Watch were measured at several planes in 1 cm resolution using an FW Bell 5180 Gauss Meter with STD18-0404 Transverse probe (unidirectional probe). Results: All iPhone 12 and Apple Watch 6 models tested have static magnetic fields significantly greater than 10 G in close proximity (1-11 mm), which attenuates to below 10 G between 11 and 20 mm. Conclusion: The findings of this study support the US Food and Drug Administration recommendation that patients keep any consumer electronic devices that may create magnetic interference, including cell phones and smart watches, at least 6 inches away from implanted medical devices, in particular pacemakers and cardiac defibrillators. Open access paper: frontiersin.org

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeexposure_assessment

Effect directionharm

PopulationNot supplied

Sample sizeNot supplied

Exposurestatic magnetic field

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Outcomes measured

Static magnetic field strength (Gauss) near devices
Separation distance at which field falls below 10 G threshold relevant to triggering magnet mode in pacemakers/ICDs

Limitations

No sample size or number of device units tested is stated in the abstract.
Study measures magnetic field strength near devices rather than clinical outcomes or confirmed device interference events.
Only specific models (iPhone 12 and Apple Watch 6) are mentioned; generalizability to other devices is not established in the abstract.

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "static magnetic field",
    "source": "smartphone and smart watch",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Static magnetic field strength (Gauss) near devices",
    "Separation distance at which field falls below 10 G threshold relevant to triggering magnet mode in pacemakers/ICDs"
  ],
  "main_findings": "Measured static magnetic fields from iPhone 12 models and Apple Watch 6 were reported to be >10 G at close proximity (1–11 mm) and to attenuate to <10 G between 11 and 20 mm. The authors conclude this supports FDA advice to keep such consumer devices at least 6 inches from implanted cardiac devices.",
  "effect_direction": "harm",
  "limitations": [
    "No sample size or number of device units tested is stated in the abstract.",
    "Study measures magnetic field strength near devices rather than clinical outcomes or confirmed device interference events.",
    "Only specific models (iPhone 12 and Apple Watch 6) are mentioned; generalizability to other devices is not established in the abstract."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "static magnetic field",
    "iPhone 12",
    "Apple Watch 6",
    "magnet mode",
    "pacemaker",
    "implantable cardioverter-defibrillator",
    "magnetic interference",
    "Gauss meter",
    "separation distance"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.2,
      "reason": "Mentions electromagnetic interference thresholds and safety-relevant separation distances, but no explicit WHO/ICNIRP content in abstract."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.hrthm.2021.06.1203
PubMed: Not supplied

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