RF Safe

Lack of evidence of areas of slow conduction early after radiofrequency current application at porcine atrial myocardium.

Pacing and clinical electrophysiology : PACE · 1996 · No effect · Low evidence

← Research stream
No effectLow evidencePaper 4272

In viable tissue surrounding radiofrequency current lesions, measured action potential parameters showed no significant differences among preparations. No intracellular action potentials were recorded from lesion surfaces, surrounding tissue was sharply demar…

Study snapshot

PublicationPacing and clinical electrophysiology : PACE · 1996
Study typeanimal
Reported directionNo effect
Evidence ratingLow

Abstract

Electrophysiological sequelae after creation of atrial myocardial lesions by radiofrequency current (RFC) application have not been studied in vitro. During general anesthesia, a steerable 6 French electrode catheter, equipped with a thermistor at the 4-mm tip electrode, was positioned at the lateral atrial aspect of the tricuspid valve annulus in 5 piglets (German Landrace, mean body weight 12.5 kg). Temperature-guided (75 degrees C) RFC (500 kHz) was delivered over 30 seconds. Forty-eight hours later, the hearts were removed and placed in ice-cold Turner's solution. The right atria were dissected, and the RFC lesions with surrounding tissue were cut out and transferred to an organ bath according to Steiert. Preparations were superfused with Turner's solution at 37 degrees C. Pacing of the viable tissue at the border of the preparations was accomplished at a cycle length of 500 ms. Whole atrial preparations were impaled (76 to 150 impalements per specimen) with KCl capillary microelectrodes containing 3 MKCl. In the surrounding viable tissue of the five preparations, mean maximum diastolic transmembrane potential ranged from -61.3 to -63.7 mV, mean action potential duration at 90% repolarization ranged from 135.2 to 156.1 ms, and mean maximum upstroke velocity of phase 0 of the action potential was between 104.7 and 112.9 V/sec. Statistical analysis revealed no significant differences among all 3 variables. No intracellular action potential was recorded from the surface of all 5 lesions. The surrounding tissue was sharply demarcated, with unaltered transmembrane action potential characteristics in the vicinity of the lesions. Areas of slow conduction were not observed. Lack of evidence of areas of slow conduction after RFC application to the atrial myocardium may imply that this technique is safe regarding occurrence of atrial tachyarrhythmias.

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 typeanimal
Effect directionno_effect
PopulationPiglets (German Landrace) under general anesthesia; isolated right atrial preparations studied in vitro 48 hours post-ablation
Sample size5
ExposureRF · 0.5 MHz · 30 seconds
Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

In viable tissue surrounding radiofrequency current lesions, measured action potential parameters showed no significant differences among preparations. No intracellular action potentials were recorded from lesion surfaces, surrounding tissue was sharply demarcated with unaltered action potential characteristics near lesions, and areas of slow conduction were not observed.

Outcomes measured

  • Transmembrane potential characteristics (maximum diastolic potential, action potential duration at 90% repolarization, maximum upstroke velocity) in tissue surrounding lesions
  • Presence/absence of intracellular action potentials on lesion surface
  • Observation of areas of slow conduction
  • Implication for atrial tachyarrhythmias safety (inference)

Limitations

  • Small sample size (5 piglets)
  • In vitro electrophysiology performed 48 hours after in vivo lesion creation; findings may not generalize to other time points
  • Study focused on atrial tissue near lesions; arrhythmia outcomes were not directly measured (safety implication is inferential)
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": "medical ablation (radiofrequency current via catheter)",
    "frequency_mhz": 0.5,
    "sar_wkg": null,
    "duration": "30 seconds"
  },
  "population": "Piglets (German Landrace) under general anesthesia; isolated right atrial preparations studied in vitro 48 hours post-ablation",
  "sample_size": 5,
  "outcomes": [
    "Transmembrane potential characteristics (maximum diastolic potential, action potential duration at 90% repolarization, maximum upstroke velocity) in tissue surrounding lesions",
    "Presence/absence of intracellular action potentials on lesion surface",
    "Observation of areas of slow conduction",
    "Implication for atrial tachyarrhythmias safety (inference)"
  ],
  "main_findings": "In viable tissue surrounding radiofrequency current lesions, measured action potential parameters showed no significant differences among preparations. No intracellular action potentials were recorded from lesion surfaces, surrounding tissue was sharply demarcated with unaltered action potential characteristics near lesions, and areas of slow conduction were not observed.",
  "effect_direction": "no_effect",
  "limitations": [
    "Small sample size (5 piglets)",
    "In vitro electrophysiology performed 48 hours after in vivo lesion creation; findings may not generalize to other time points",
    "Study focused on atrial tissue near lesions; arrhythmia outcomes were not directly measured (safety implication is inferential)"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency current",
    "500 kHz",
    "atrial myocardium",
    "catheter ablation",
    "porcine",
    "slow conduction",
    "action potential",
    "electrophysiology"
  ],
  "suggested_hubs": [
    {
      "slug": "other",
      "weight": 0.35,
      "reason": "Radiofrequency energy used for cardiac ablation; not an environmental/consumer EMF exposure context."
    }
  ]
}
AI can be wrong. Always verify against the paper.

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: 10.1111/j.1540-8159.1996.tb03271.x
PubMed: 8945087

Read the original paper →

Related papers

← Back to the Research Library