The role of electrolyte in lesion size using an irrigated radiofrequency electrode.

Journal of investigative surgery : the official journal of the Academy of Surgical Research · 1997 · Mixed · Low evidence

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MixedLow evidencePaper 4110

Study snapshot

PublicationJournal of investigative surgery : the official journal of the Academy of Surgical Research · 1997

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

Multiple attempts have been made to eliminate atrial fibrillation by performing the surgical maze procedure with radiofrequency energy. Currently, this is limited because of the risk of atrial perforation and the lack of transmural penetration. Saline irrigation has been investigated as a method of radiofrequency cautery tip cooling to prevent rapid temperature and impedance rises, which have been shown to lead to perforation or decreased radiofrequency penetration after eschar formation. There are few data on the influence that different types of electrolyte irrigation solutions have on lesion depth. Using a novel hollow cautery pen, we infused either an electrolyte solution (0.9%, 3%, 14.6%, or 23.4% sodium chloride), a nonelectrolyte solution (1.5% glycine), or no irrigation to produce 819 lesions on 14 left ventricles in swine using radiofrequency energy (450+/-10 kHz) applied at two output settings (20 and 75 watts). The nonelectrolyte solution increased lesion depth compared with no infusion at 20 watts but produced shallower lesion depths compared with electrolyte solutions at 75 watts. Compared with the other electrolyte solutions, the 0.9% sodium chloride solution produced the deepest lesions (3.34+/-0.06 mm) at 75 watts (p < 0.001). As the concentration of electrolyte increased, lesion depth decreased unless generator output increased. Formation of eschar and tissue destruction was seen in the noninfusion and nonelectrolyte groups but not in the electrolyte group. A conductive media coupled with radiofrequency energy allowed for greater lesion depth than irrigated cooling with a nonelectrolyte solution or no irrigation. There was an inverse relationship between electrolyte concentration and lesion depth. We conclude that the concentration of electrolyte irrigant is an important consideration when choosing a solution to improve transmural penetration and decrease the risk of tissue destruction from radiofrequency energy.

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AI evidence extraction

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Study typeanimal

Effect directionmixed

PopulationSwine (14 left ventricles)

Sample size14

Exposure0.45 MHz

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In swine left ventricles, lesion depth produced by radiofrequency energy (450±10 kHz) depended on irrigation solution type and electrolyte concentration. At 75 W, 0.9% sodium chloride produced the deepest lesions (3.34±0.06 mm; p<0.001 vs other electrolyte solutions), and increasing electrolyte concentration was associated with decreased lesion depth unless generator output increased. Eschar formation and tissue destruction were observed in the noninfusion and nonelectrolyte (glycine) groups but not in the electrolyte (saline) groups.

Outcomes measured

Lesion depth/size
Eschar formation
Tissue destruction
Impedance/temperature rise (context for mechanism)

Limitations

Animal (swine) model; applicability to humans not stated
Ex vivo/isolated tissue context implied (left ventricles used), clinical outcomes not assessed
Duration of RF application not reported in abstract
Lesion depth reported; other lesion characteristics (e.g., width, transmurality) not fully detailed in abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": null,
    "source": "radiofrequency surgical electrode (irrigated radiofrequency cautery pen)",
    "frequency_mhz": 0.45,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Swine (14 left ventricles)",
  "sample_size": 14,
  "outcomes": [
    "Lesion depth/size",
    "Eschar formation",
    "Tissue destruction",
    "Impedance/temperature rise (context for mechanism)"
  ],
  "main_findings": "In swine left ventricles, lesion depth produced by radiofrequency energy (450±10 kHz) depended on irrigation solution type and electrolyte concentration. At 75 W, 0.9% sodium chloride produced the deepest lesions (3.34±0.06 mm; p<0.001 vs other electrolyte solutions), and increasing electrolyte concentration was associated with decreased lesion depth unless generator output increased. Eschar formation and tissue destruction were observed in the noninfusion and nonelectrolyte (glycine) groups but not in the electrolyte (saline) groups.",
  "effect_direction": "mixed",
  "limitations": [
    "Animal (swine) model; applicability to humans not stated",
    "Ex vivo/isolated tissue context implied (left ventricles used), clinical outcomes not assessed",
    "Duration of RF application not reported in abstract",
    "Lesion depth reported; other lesion characteristics (e.g., width, transmurality) not fully detailed in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency energy",
    "irrigation",
    "electrolyte",
    "sodium chloride",
    "glycine",
    "lesion depth",
    "maze procedure",
    "atrial fibrillation",
    "swine",
    "cautery pen"
  ],
  "suggested_hubs": [
    {
      "slug": "engineering",
      "weight": 0.6,
      "reason": "Bench/animal evaluation of RF electrode irrigation parameters affecting lesion depth and tissue effects."
    }
  ]
}

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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: 10.3109/08941939709099597
PubMed: 9654390

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