The effects of electrode-tissue contact on radiofrequency lesion generation.

Pacing and clinical electrophysiology : PACE · 1997 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 4144

Study snapshot

PublicationPacing and clinical electrophysiology : PACE · 1997

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

During the generation of radiofrequency (RF) lesions in the ventricular myocardium, the maintenance of adequate electrode-tissue contact is critically important. In this study, lesion dimensions and temperature and impedance changes were evaluated while controlling electrode-tissue contact levels (-5, 0, +1, and +3 mm) and power levels (10, 20, and 30 W). This data was used to assess the ability of impedance and temperature monitoring to provide useful information about the quality of electrode-tissue contact. The results show that as the electrode-tissue contact increases, so does the amount of temperature rise. With the electrode floating in blood (-5 contact), the average maximum temperature increase with 20 and 30 W was only 7 +/- 1 and 11 +/- 2 degrees C, respectively. At 20 and 30 W the temperature plateaued shortly after the initiation of power application. With good electrode-tissue contact (+1 mm or +3 mm), the temperature increase within the first 10 seconds was significantly greater than the temperature increase from baseline with poor contact (0 mm or -5 mm) and reached a maximum of 60 +/- 1 degrees C after 60 seconds of power application. As the electrode-tissue contact increased, so did the rate and level of impedance decrease. However, the rate of impedance decrease was slower compared to the rate of temperature rise. With the electrode floating in blood, the maximum impedance decreases with 20 and 30 W were 6 +/- 6 omega and 9 +/- 5 omega, respectively. The impedances plateaued after a few seconds of power application. With the electrode in good contact, the maximum impedance decreases with 20 and 30 W were 25 +/- 2 omega and 20 +/- 6 omega, respectively. In these cases the rate of the impedance decrease plateaued after 40 seconds of power application. The increase in lesion diameter and depth correlate well with decreasing impedance and increasing temperature. However, lesion depth appears to correlate better with impedance than temperature. We conclude that, since the electrode-tissue contact is not known prior to the application of power to the endocardium, in the absence of a temperature control system, the power should initially be set at a low level. The power should be increased slowly over 20-30 seconds, and then maintained at its final level for at least 90 seconds to allow for maximal lesion depth maturation. The power level should be lowered if the impedance drop exceeds 15 omega.

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AI evidence extraction

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Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureRF · up to 90 seconds (lesion generation; temperature/impedance tracked over first 10–60 seconds; recommendation to maintain final power ≥90 seconds)

Evidence strengthInsufficientConfidence: 66% · Peer reviewed: yes

Main findings

Lesion dimensions, temperature, and impedance changes were evaluated across electrode-tissue contact levels (-5, 0, +1, +3 mm) and power levels (10, 20, 30 W). Greater electrode-tissue contact produced larger temperature rises and larger/faster impedance decreases; lesion diameter and depth correlated with increasing temperature and decreasing impedance, with lesion depth reported to correlate better with impedance than temperature. The authors recommend starting at low power and increasing slowly over 20–30 seconds, maintaining final power for at least 90 seconds, and lowering power if impedance drop exceeds 15 ohms.

Outcomes measured

Lesion dimensions (diameter, depth)
Temperature rise
Impedance change

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "RF",
    "source": "medical radiofrequency ablation",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "up to 90 seconds (lesion generation; temperature/impedance tracked over first 10–60 seconds; recommendation to maintain final power ≥90 seconds)"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Lesion dimensions (diameter, depth)",
    "Temperature rise",
    "Impedance change"
  ],
  "main_findings": "Lesion dimensions, temperature, and impedance changes were evaluated across electrode-tissue contact levels (-5, 0, +1, +3 mm) and power levels (10, 20, 30 W). Greater electrode-tissue contact produced larger temperature rises and larger/faster impedance decreases; lesion diameter and depth correlated with increasing temperature and decreasing impedance, with lesion depth reported to correlate better with impedance than temperature. The authors recommend starting at low power and increasing slowly over 20–30 seconds, maintaining final power for at least 90 seconds, and lowering power if impedance drop exceeds 15 ohms.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.66,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency lesion",
    "catheter ablation",
    "electrode-tissue contact",
    "ventricular myocardium",
    "temperature monitoring",
    "impedance monitoring",
    "lesion depth",
    "lesion diameter"
  ],
  "suggested_hubs": [
    {
      "slug": "engineering",
      "weight": 0.72,
      "reason": "Study focuses on RF lesion generation parameters (contact, power) and monitoring (temperature/impedance) rather than environmental EMF exposure."
    }
  ]
}

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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: 10.1111/j.1540-8159.1997.tb05458.x
PubMed: 9455749

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