Discrepancies between catheter tip and tissue temperature in cooled-tip ablation: Relevance to guiding left atrial ablation

G. Keith Bruce, T. Jared Bunch, Mark A. Milton, Alvaro Sarabanda, Susan B. Johnson, Douglas L Packer

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

Background - It is not known whether catheter tip temperatures with a cooled-tip ablation can be reliably extrapolated to estimate actual tissue temperatures. The relationship between catheter tip temperatures, tissue temperatures, power, and microbubble formation is not known. Methods and Results - Nine dogs underwent 111 radiofrequency energy deliveries at the pulmonary vein ostia with a cooled-tip catheter. Catheter tip and tissue temperatures were markedly discrepant. Catheter tip temperature plateaus at 36°C to 39°C with increasing power, whereas tissue temperature increases to a mean of 75±3°C at 45 W (maximum temperature >100°C). Seventy-two energy deliveries were performed, titrating power to microbubble formation guided by intracardiac echocardiography. Type I and II microbubble formation occurred in 45 (63%) and 19 (26%) ablations, respectively. Type I microbubble emergence occurred at lower powers (21±8 versus 26±4 W; P=0.05), catheter tip temperatures (38±5°C versus 48±10°C; P=0.02), and tissue temperatures (65±19°C versus 81±9°C; P<0.001) than type II microbubble formation. Maximum impedance decreases during ablation before microbubble formation were less with type I microbubble (20±9 versus 37±11 Ω; P<0.001) compared with type II microbubbles. One quarter of type I microbubbles abruptly transitioned to type II microbubbles with significant changes in power or catheter tip temperature. No microbubbles were seen in 19 ablations (26%) despite powers up to 26±9 W and tissue temperatures up to 81±17°C. Conclusions - Catheter tip and tissue temperatures are markedly discrepant during cooled-tip ablation. Type I and II microbubble formation occurs at overlapping power and catheter tip and tissue temperature ranges. Neither the absence of microbubbles nor the presence of type I microbubble formation ensures against excessive tissue heating. The appearance of microbubbles may indicate possible tissue overheating and signal a need to decrease energy.

Original languageEnglish (US)
Pages (from-to)954-960
Number of pages7
JournalCirculation
Volume112
Issue number7
DOIs
StatePublished - Aug 16 2005

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Microbubbles
Catheters
Temperature
Pulmonary Veins
Electric Impedance

Keywords

  • Ablation
  • Arrhythmia
  • Atrium
  • Catheter ablation
  • Echocardiography

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Discrepancies between catheter tip and tissue temperature in cooled-tip ablation : Relevance to guiding left atrial ablation. / Bruce, G. Keith; Bunch, T. Jared; Milton, Mark A.; Sarabanda, Alvaro; Johnson, Susan B.; Packer, Douglas L.

In: Circulation, Vol. 112, No. 7, 16.08.2005, p. 954-960.

Research output: Contribution to journalArticle

Bruce, G. Keith ; Bunch, T. Jared ; Milton, Mark A. ; Sarabanda, Alvaro ; Johnson, Susan B. ; Packer, Douglas L. / Discrepancies between catheter tip and tissue temperature in cooled-tip ablation : Relevance to guiding left atrial ablation. In: Circulation. 2005 ; Vol. 112, No. 7. pp. 954-960.
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title = "Discrepancies between catheter tip and tissue temperature in cooled-tip ablation: Relevance to guiding left atrial ablation",
abstract = "Background - It is not known whether catheter tip temperatures with a cooled-tip ablation can be reliably extrapolated to estimate actual tissue temperatures. The relationship between catheter tip temperatures, tissue temperatures, power, and microbubble formation is not known. Methods and Results - Nine dogs underwent 111 radiofrequency energy deliveries at the pulmonary vein ostia with a cooled-tip catheter. Catheter tip and tissue temperatures were markedly discrepant. Catheter tip temperature plateaus at 36°C to 39°C with increasing power, whereas tissue temperature increases to a mean of 75±3°C at 45 W (maximum temperature >100°C). Seventy-two energy deliveries were performed, titrating power to microbubble formation guided by intracardiac echocardiography. Type I and II microbubble formation occurred in 45 (63{\%}) and 19 (26{\%}) ablations, respectively. Type I microbubble emergence occurred at lower powers (21±8 versus 26±4 W; P=0.05), catheter tip temperatures (38±5°C versus 48±10°C; P=0.02), and tissue temperatures (65±19°C versus 81±9°C; P<0.001) than type II microbubble formation. Maximum impedance decreases during ablation before microbubble formation were less with type I microbubble (20±9 versus 37±11 Ω; P<0.001) compared with type II microbubbles. One quarter of type I microbubbles abruptly transitioned to type II microbubbles with significant changes in power or catheter tip temperature. No microbubbles were seen in 19 ablations (26{\%}) despite powers up to 26±9 W and tissue temperatures up to 81±17°C. Conclusions - Catheter tip and tissue temperatures are markedly discrepant during cooled-tip ablation. Type I and II microbubble formation occurs at overlapping power and catheter tip and tissue temperature ranges. Neither the absence of microbubbles nor the presence of type I microbubble formation ensures against excessive tissue heating. The appearance of microbubbles may indicate possible tissue overheating and signal a need to decrease energy.",
keywords = "Ablation, Arrhythmia, Atrium, Catheter ablation, Echocardiography",
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T1 - Discrepancies between catheter tip and tissue temperature in cooled-tip ablation

T2 - Relevance to guiding left atrial ablation

AU - Bruce, G. Keith

AU - Bunch, T. Jared

AU - Milton, Mark A.

AU - Sarabanda, Alvaro

AU - Johnson, Susan B.

AU - Packer, Douglas L

PY - 2005/8/16

Y1 - 2005/8/16

N2 - Background - It is not known whether catheter tip temperatures with a cooled-tip ablation can be reliably extrapolated to estimate actual tissue temperatures. The relationship between catheter tip temperatures, tissue temperatures, power, and microbubble formation is not known. Methods and Results - Nine dogs underwent 111 radiofrequency energy deliveries at the pulmonary vein ostia with a cooled-tip catheter. Catheter tip and tissue temperatures were markedly discrepant. Catheter tip temperature plateaus at 36°C to 39°C with increasing power, whereas tissue temperature increases to a mean of 75±3°C at 45 W (maximum temperature >100°C). Seventy-two energy deliveries were performed, titrating power to microbubble formation guided by intracardiac echocardiography. Type I and II microbubble formation occurred in 45 (63%) and 19 (26%) ablations, respectively. Type I microbubble emergence occurred at lower powers (21±8 versus 26±4 W; P=0.05), catheter tip temperatures (38±5°C versus 48±10°C; P=0.02), and tissue temperatures (65±19°C versus 81±9°C; P<0.001) than type II microbubble formation. Maximum impedance decreases during ablation before microbubble formation were less with type I microbubble (20±9 versus 37±11 Ω; P<0.001) compared with type II microbubbles. One quarter of type I microbubbles abruptly transitioned to type II microbubbles with significant changes in power or catheter tip temperature. No microbubbles were seen in 19 ablations (26%) despite powers up to 26±9 W and tissue temperatures up to 81±17°C. Conclusions - Catheter tip and tissue temperatures are markedly discrepant during cooled-tip ablation. Type I and II microbubble formation occurs at overlapping power and catheter tip and tissue temperature ranges. Neither the absence of microbubbles nor the presence of type I microbubble formation ensures against excessive tissue heating. The appearance of microbubbles may indicate possible tissue overheating and signal a need to decrease energy.

AB - Background - It is not known whether catheter tip temperatures with a cooled-tip ablation can be reliably extrapolated to estimate actual tissue temperatures. The relationship between catheter tip temperatures, tissue temperatures, power, and microbubble formation is not known. Methods and Results - Nine dogs underwent 111 radiofrequency energy deliveries at the pulmonary vein ostia with a cooled-tip catheter. Catheter tip and tissue temperatures were markedly discrepant. Catheter tip temperature plateaus at 36°C to 39°C with increasing power, whereas tissue temperature increases to a mean of 75±3°C at 45 W (maximum temperature >100°C). Seventy-two energy deliveries were performed, titrating power to microbubble formation guided by intracardiac echocardiography. Type I and II microbubble formation occurred in 45 (63%) and 19 (26%) ablations, respectively. Type I microbubble emergence occurred at lower powers (21±8 versus 26±4 W; P=0.05), catheter tip temperatures (38±5°C versus 48±10°C; P=0.02), and tissue temperatures (65±19°C versus 81±9°C; P<0.001) than type II microbubble formation. Maximum impedance decreases during ablation before microbubble formation were less with type I microbubble (20±9 versus 37±11 Ω; P<0.001) compared with type II microbubbles. One quarter of type I microbubbles abruptly transitioned to type II microbubbles with significant changes in power or catheter tip temperature. No microbubbles were seen in 19 ablations (26%) despite powers up to 26±9 W and tissue temperatures up to 81±17°C. Conclusions - Catheter tip and tissue temperatures are markedly discrepant during cooled-tip ablation. Type I and II microbubble formation occurs at overlapping power and catheter tip and tissue temperature ranges. Neither the absence of microbubbles nor the presence of type I microbubble formation ensures against excessive tissue heating. The appearance of microbubbles may indicate possible tissue overheating and signal a need to decrease energy.

KW - Ablation

KW - Arrhythmia

KW - Atrium

KW - Catheter ablation

KW - Echocardiography

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