The use of low-level electromagnetic fields to suppress atrial fibrillation.

Heart rhythm · 2015 · Benefit · Low evidence

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BenefitLow evidencePaper 4640

Study snapshot

PublicationHeart rhythm · 2015

Study typeanimal

Reported directionBenefit

Evidence ratingLow

Abstract

BACKGROUND: Extremely low-level electromagnetic fields have been proposed to cause significant changes in neural networks. OBJECTIVE: We sought to investigate whether low-level electromagnetic fields can suppress atrial fibrillation (AF). METHODS: In 17 pentobarbital anesthetized dogs, bilateral thoracotomies allowed the placement of multielectrode catheters in both atria and at all pulmonary veins. AF was induced by rapid atrial pacing (RAP) or programmed atrial extrastimulation. At baseline and end of each hour of RAP, during sinus rhythm, atrial programmed stimulation gave both the effective refractory period (ERP) and the width of the window of vulnerability. The latter was a measure of AF inducibility. Microelectrodes inserted into the anterior right ganglionated plexi recorded neural firing. Helmholtz coils were powered by a function generator inducing an electromagnetic field (EMF; 0.034 μG, 0.952 Hz). The study sample was divided into 2 groups: group 1 (n = 7)-application of EMF to both cervical vagal trunks; group 2 (n = 10)-application of EMF across the chest so that the heart was located in the center of the coil. RESULTS: In group 1, EMF induced a progressive increase in AF threshold at all pulmonary vein and atrial sites (all P < .05). In group 2, the atrial ERP progressively shortened and ERP dispersion and window of vulnerability progressively increased (P < .05 compared to baseline values) during 3 hours of RAP and then returned to baseline values during 3 hours of combined application of RAP and EMF (P < .05 compared to the end of the third hour of RAP). The frequency and amplitude of the neural activity recorded from the anterior right ganglionated plexi were markedly suppressed by EMF in both groups. CONCLUSION: Pulsed EMF applied to the vagal trunks or noninvasively across the chest can significantly reverse AF inducibility.

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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 typeanimal

Effect directionbenefit

PopulationPentobarbital-anesthetized dogs with induced atrial fibrillation

Sample size17

ExposureELF · 3 hours combined application of RAP and EMF (after 3 hours of RAP alone); EMF also applied in group 1 (timing not further specified)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In dogs with induced AF, application of a very low-level EMF (0.034 μG, 0.952 Hz) to cervical vagal trunks increased AF threshold at pulmonary vein and atrial sites. When applied across the chest after 3 hours of rapid atrial pacing, EMF reversed pacing-associated increases in AF inducibility measures (window of vulnerability, ERP dispersion) and returned ERP changes toward baseline; neural activity recorded from the anterior right ganglionated plexi was markedly suppressed by EMF in both groups.

Outcomes measured

Atrial fibrillation (AF) threshold
AF inducibility (window of vulnerability)
Atrial effective refractory period (ERP)
ERP dispersion
Neural firing/activity in anterior right ganglionated plexi (frequency and amplitude)

Limitations

Animal study in anesthetized dogs; generalizability to humans not addressed in abstract
Small sample size (n=17)
AF was experimentally induced (rapid atrial pacing/programmed stimulation), which may not reflect clinical AF
Exposure details beyond field strength and frequency (e.g., waveform specifics, duty cycle) not fully described in abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "3 hours combined application of RAP and EMF (after 3 hours of RAP alone); EMF also applied in group 1 (timing not further specified)"
  },
  "population": "Pentobarbital-anesthetized dogs with induced atrial fibrillation",
  "sample_size": 17,
  "outcomes": [
    "Atrial fibrillation (AF) threshold",
    "AF inducibility (window of vulnerability)",
    "Atrial effective refractory period (ERP)",
    "ERP dispersion",
    "Neural firing/activity in anterior right ganglionated plexi (frequency and amplitude)"
  ],
  "main_findings": "In dogs with induced AF, application of a very low-level EMF (0.034 μG, 0.952 Hz) to cervical vagal trunks increased AF threshold at pulmonary vein and atrial sites. When applied across the chest after 3 hours of rapid atrial pacing, EMF reversed pacing-associated increases in AF inducibility measures (window of vulnerability, ERP dispersion) and returned ERP changes toward baseline; neural activity recorded from the anterior right ganglionated plexi was markedly suppressed by EMF in both groups.",
  "effect_direction": "benefit",
  "limitations": [
    "Animal study in anesthetized dogs; generalizability to humans not addressed in abstract",
    "Small sample size (n=17)",
    "AF was experimentally induced (rapid atrial pacing/programmed stimulation), which may not reflect clinical AF",
    "Exposure details beyond field strength and frequency (e.g., waveform specifics, duty cycle) not fully described in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low-level electromagnetic fields",
    "ELF-EMF",
    "pulsed EMF",
    "atrial fibrillation",
    "vagal trunks",
    "ganglionated plexi",
    "neural activity",
    "rapid atrial pacing",
    "Helmholtz coils",
    "dog model"
  ],
  "suggested_hubs": []
}

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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.2014.12.022
PubMed: 25533588

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