Magnetic Field-Induced Interactions between Phones Containing Magnets and Cardiovascular Implantable Electronic Devices - Flip it to be Safe?

Abstract

Magnetic Field-Induced Interactions between Phones Containing Magnets and Cardiovascular Implantable Electronic Devices - Flip it to be Safe? Lacour P, Dang PL, Heinzel FR, Parwani AS, Bähr F, Kucher A, Hohendanner F, Niendorf T, Rahimi F, Saha N, Han H, Rubarth K, Sherif M, Boldt LH, Pieske B, Blaschke F. Magnetic Field-Induced Interactions between Phones Containing Magnets and Cardiovascular Implantable Electronic Devices - Flip it to be Safe? Heart Rhythm. 2021 Nov 9:S1547-5271(21)02334-1. doi: 10.1016/j.hrthm.2021.11.010. Abstract Background: Recent case reports and small studies have reported activation of the magnet-sensitive switches in cardiovascular implantable electronic devices (CIED) by the new iPhone 12 series, initiating asynchronous pacing in pacemakers and suspension of anti-tachycardia therapies in ICDs. Objective and methods: We performed a prospective single-center observational study to quantify the risk of magnetic field interactions of the iPhone 12 with CIEDs. A representative model of each CIED series from all manufacturers was tested ex vivo. Incidence and minimum distance necessary for magnet mode triggering were analyzed in 164 CIED patients with either the front or the back of the phone facing the device. The magnetic field of the iPhone 12 was analyzed using a 3-axis hall probe. Results: Ex vivo, magnetic interferences occurred in 84.6% with the back compared to 46.2% with the front of the iPhone 12 facing the CIED. In vivo, activation of the magnet-sensitive switch occurred in 30 CIED patients (18.3%; 21 pacemaker, 9 ICDs) when the iPhone 12 was placed in close proximity over the CIED pocket and the back of the phone was facing the skin. Multiple binary logistic regression analysis identified the implantation depth (95% confidence interval [CI], 0.02 to 0.24) as independent predictor of magnet-sensitive switch activation. Conclusion: Magnetic field interactions occur only in close proximity, and with precise alignment of the iPhone 12 and CIEDs. It is important to advise CIED patients to not put the iPhone 12 directly on the skin above the CIED. Further recommendations are not necessary. Open access paper: heartrhythmjournal.com

AI evidence extraction

Main findings

In vivo, magnet-sensitive switch activation occurred in 30/164 CIED patients (18.3%; 21 pacemaker, 9 ICDs) when an iPhone 12 was placed in close proximity over the CIED pocket with the back of the phone facing the skin. Ex vivo, magnetic interferences occurred in 84.6% with the back versus 46.2% with the front of the phone facing the CIED; implantation depth was identified as an independent predictor of activation.

Outcomes measured

• Magnet-sensitive switch activation / magnet mode triggering in CIEDs
• Minimum distance necessary for magnet mode triggering
• Incidence of magnetic interference ex vivo and in vivo
• Predictors of magnet-sensitive switch activation (implantation depth)

Limitations

• Prospective single-center observational study
• Ex vivo testing used representative models rather than each patient’s implanted device (details not provided)
• Exposure conditions involved close proximity and precise alignment over the CIED pocket; generalizability to typical real-world phone use is unclear from the abstract
• Minimum distance values and full regression details are not reported in the abstract

Suggested hubs

• medical-implants (0.95)
  Study evaluates magnetic interactions between a smartphone containing magnets and pacemakers/ICDs (CIEDs).
• mobile-phones (0.7)
  Exposure source is an iPhone 12 placed near the implant pocket.

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    "exposure": {
        "band": null,
        "source": "mobile phone (iPhone 12 with magnets)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Patients with cardiovascular implantable electronic devices (CIEDs) (pacemakers and ICDs)",
    "sample_size": 164,
    "outcomes": [
        "Magnet-sensitive switch activation / magnet mode triggering in CIEDs",
        "Minimum distance necessary for magnet mode triggering",
        "Incidence of magnetic interference ex vivo and in vivo",
        "Predictors of magnet-sensitive switch activation (implantation depth)"
    ],
    "main_findings": "In vivo, magnet-sensitive switch activation occurred in 30/164 CIED patients (18.3%; 21 pacemaker, 9 ICDs) when an iPhone 12 was placed in close proximity over the CIED pocket with the back of the phone facing the skin. Ex vivo, magnetic interferences occurred in 84.6% with the back versus 46.2% with the front of the phone facing the CIED; implantation depth was identified as an independent predictor of activation.",
    "effect_direction": "harm",
    "limitations": [
        "Prospective single-center observational study",
        "Ex vivo testing used representative models rather than each patient’s implanted device (details not provided)",
        "Exposure conditions involved close proximity and precise alignment over the CIED pocket; generalizability to typical real-world phone use is unclear from the abstract",
        "Minimum distance values and full regression details are not reported in the abstract"
    ],
    "evidence_strength": "moderate",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "iPhone 12",
        "magnets",
        "magnetic field",
        "cardiovascular implantable electronic devices",
        "CIED",
        "pacemaker",
        "ICD",
        "magnet mode",
        "asynchronous pacing",
        "anti-tachycardia therapy suspension",
        "hall probe"
    ],
    "suggested_hubs": [
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            "slug": "medical-implants",
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            "reason": "Study evaluates magnetic interactions between a smartphone containing magnets and pacemakers/ICDs (CIEDs)."
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            "reason": "Exposure source is an iPhone 12 placed near the implant pocket."
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}

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