Why a large tip electrode makes a deeper radiofrequency lesion: Effects of increase in electrode cooling and electrode-tissue interface area

Kenichiro Otomo, William S. Yamanashi, Claudio Tondo, Matthias Antz, Jonathan Bussey, Jan V. Pitha, Mauricio Arruda, Hiroshi Nakagawa, Fred H M Wittkampf, Ralph Lazzara, Warren M. Jackman

Research output: Contribution to journalArticle

Abstract

Introduction: Increasing electrode size allows an increase in radiofrequency lesion depth. The purpose of this study was to examine the roles of added electrode cooling and electrode-tissue interface area in producing deeper lesions. Methods and Results: In 10 dogs, the thigh muscle was exposed and superfused with heparinized blood. An 8-French catheter with 4- or 8-mm tip electrode was positioned against the muscle with a blood flow of 350 mL/min directed around the electrode. Radiofrequency current was delivered using four methods: (1) electrode perpendicular to the muscle, using variable voltage to maintain the electrode-tissue interface temperature at 60°C; (2) same except the surrounding blood was stationary; (3) perpendicular electrode position, maintaining tissue temperature (3.5-mm depth) at 90°C; and (4) electrode parallel to the muscle, maintaining tissue temperature at 90°C. Electrode-tissue interface temperature, tissue temperature (3.5- and 7.0-mm depths), and lesion size were compared between the 4- and 8-mm electrodes in each method. In Methods 1 and 2, the tissue temperatures and lesion depth were greater with the 8-mm electrode. These differences were smaller without blood flow, suggesting the improved convective cooling of the larger electrode resulted in greater power delivered to the tissue at the same electrode-tissue interface temperature. In Method 3 (same tissue current density), the electrode-tissue interface temperature was significantly lower with the 8-mm electrode. With parallel orientation and same tissue temperature at 3.5-mm depth (Method 4), the tissue temperature at 7.0-mm depth and lesion depth were greater with the 8- mm electrode, suggesting increased conductive heating due to larger volume of resistive heating because of the larger electrode-tissue interface area. Conclusion: With a larger electrode, both increased cooling and increased electrode-tissue interface area increase volume of resistive heating and lesion depth.

Original languageEnglish
Pages (from-to)47-54
Number of pages8
JournalJournal of Cardiovascular Electrophysiology
Volume9
Issue number1
Publication statusPublished - 1998

Fingerprint

Electrodes
Temperature
Heating
Muscles
Thigh

Keywords

  • Catheter ablation
  • Electrode cooling
  • Electrode size
  • Electrode-tissue interface area
  • Lesion size
  • Radiofrequency

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology

Cite this

Why a large tip electrode makes a deeper radiofrequency lesion : Effects of increase in electrode cooling and electrode-tissue interface area. / Otomo, Kenichiro; Yamanashi, William S.; Tondo, Claudio; Antz, Matthias; Bussey, Jonathan; Pitha, Jan V.; Arruda, Mauricio; Nakagawa, Hiroshi; Wittkampf, Fred H M; Lazzara, Ralph; Jackman, Warren M.

In: Journal of Cardiovascular Electrophysiology, Vol. 9, No. 1, 1998, p. 47-54.

Research output: Contribution to journalArticle

Otomo, K, Yamanashi, WS, Tondo, C, Antz, M, Bussey, J, Pitha, JV, Arruda, M, Nakagawa, H, Wittkampf, FHM, Lazzara, R & Jackman, WM 1998, 'Why a large tip electrode makes a deeper radiofrequency lesion: Effects of increase in electrode cooling and electrode-tissue interface area', Journal of Cardiovascular Electrophysiology, vol. 9, no. 1, pp. 47-54.
Otomo, Kenichiro ; Yamanashi, William S. ; Tondo, Claudio ; Antz, Matthias ; Bussey, Jonathan ; Pitha, Jan V. ; Arruda, Mauricio ; Nakagawa, Hiroshi ; Wittkampf, Fred H M ; Lazzara, Ralph ; Jackman, Warren M. / Why a large tip electrode makes a deeper radiofrequency lesion : Effects of increase in electrode cooling and electrode-tissue interface area. In: Journal of Cardiovascular Electrophysiology. 1998 ; Vol. 9, No. 1. pp. 47-54.
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abstract = "Introduction: Increasing electrode size allows an increase in radiofrequency lesion depth. The purpose of this study was to examine the roles of added electrode cooling and electrode-tissue interface area in producing deeper lesions. Methods and Results: In 10 dogs, the thigh muscle was exposed and superfused with heparinized blood. An 8-French catheter with 4- or 8-mm tip electrode was positioned against the muscle with a blood flow of 350 mL/min directed around the electrode. Radiofrequency current was delivered using four methods: (1) electrode perpendicular to the muscle, using variable voltage to maintain the electrode-tissue interface temperature at 60°C; (2) same except the surrounding blood was stationary; (3) perpendicular electrode position, maintaining tissue temperature (3.5-mm depth) at 90°C; and (4) electrode parallel to the muscle, maintaining tissue temperature at 90°C. Electrode-tissue interface temperature, tissue temperature (3.5- and 7.0-mm depths), and lesion size were compared between the 4- and 8-mm electrodes in each method. In Methods 1 and 2, the tissue temperatures and lesion depth were greater with the 8-mm electrode. These differences were smaller without blood flow, suggesting the improved convective cooling of the larger electrode resulted in greater power delivered to the tissue at the same electrode-tissue interface temperature. In Method 3 (same tissue current density), the electrode-tissue interface temperature was significantly lower with the 8-mm electrode. With parallel orientation and same tissue temperature at 3.5-mm depth (Method 4), the tissue temperature at 7.0-mm depth and lesion depth were greater with the 8- mm electrode, suggesting increased conductive heating due to larger volume of resistive heating because of the larger electrode-tissue interface area. Conclusion: With a larger electrode, both increased cooling and increased electrode-tissue interface area increase volume of resistive heating and lesion depth.",
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T2 - Effects of increase in electrode cooling and electrode-tissue interface area

AU - Otomo, Kenichiro

AU - Yamanashi, William S.

AU - Tondo, Claudio

AU - Antz, Matthias

AU - Bussey, Jonathan

AU - Pitha, Jan V.

AU - Arruda, Mauricio

AU - Nakagawa, Hiroshi

AU - Wittkampf, Fred H M

AU - Lazzara, Ralph

AU - Jackman, Warren M.

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N2 - Introduction: Increasing electrode size allows an increase in radiofrequency lesion depth. The purpose of this study was to examine the roles of added electrode cooling and electrode-tissue interface area in producing deeper lesions. Methods and Results: In 10 dogs, the thigh muscle was exposed and superfused with heparinized blood. An 8-French catheter with 4- or 8-mm tip electrode was positioned against the muscle with a blood flow of 350 mL/min directed around the electrode. Radiofrequency current was delivered using four methods: (1) electrode perpendicular to the muscle, using variable voltage to maintain the electrode-tissue interface temperature at 60°C; (2) same except the surrounding blood was stationary; (3) perpendicular electrode position, maintaining tissue temperature (3.5-mm depth) at 90°C; and (4) electrode parallel to the muscle, maintaining tissue temperature at 90°C. Electrode-tissue interface temperature, tissue temperature (3.5- and 7.0-mm depths), and lesion size were compared between the 4- and 8-mm electrodes in each method. In Methods 1 and 2, the tissue temperatures and lesion depth were greater with the 8-mm electrode. These differences were smaller without blood flow, suggesting the improved convective cooling of the larger electrode resulted in greater power delivered to the tissue at the same electrode-tissue interface temperature. In Method 3 (same tissue current density), the electrode-tissue interface temperature was significantly lower with the 8-mm electrode. With parallel orientation and same tissue temperature at 3.5-mm depth (Method 4), the tissue temperature at 7.0-mm depth and lesion depth were greater with the 8- mm electrode, suggesting increased conductive heating due to larger volume of resistive heating because of the larger electrode-tissue interface area. Conclusion: With a larger electrode, both increased cooling and increased electrode-tissue interface area increase volume of resistive heating and lesion depth.

AB - Introduction: Increasing electrode size allows an increase in radiofrequency lesion depth. The purpose of this study was to examine the roles of added electrode cooling and electrode-tissue interface area in producing deeper lesions. Methods and Results: In 10 dogs, the thigh muscle was exposed and superfused with heparinized blood. An 8-French catheter with 4- or 8-mm tip electrode was positioned against the muscle with a blood flow of 350 mL/min directed around the electrode. Radiofrequency current was delivered using four methods: (1) electrode perpendicular to the muscle, using variable voltage to maintain the electrode-tissue interface temperature at 60°C; (2) same except the surrounding blood was stationary; (3) perpendicular electrode position, maintaining tissue temperature (3.5-mm depth) at 90°C; and (4) electrode parallel to the muscle, maintaining tissue temperature at 90°C. Electrode-tissue interface temperature, tissue temperature (3.5- and 7.0-mm depths), and lesion size were compared between the 4- and 8-mm electrodes in each method. In Methods 1 and 2, the tissue temperatures and lesion depth were greater with the 8-mm electrode. These differences were smaller without blood flow, suggesting the improved convective cooling of the larger electrode resulted in greater power delivered to the tissue at the same electrode-tissue interface temperature. In Method 3 (same tissue current density), the electrode-tissue interface temperature was significantly lower with the 8-mm electrode. With parallel orientation and same tissue temperature at 3.5-mm depth (Method 4), the tissue temperature at 7.0-mm depth and lesion depth were greater with the 8- mm electrode, suggesting increased conductive heating due to larger volume of resistive heating because of the larger electrode-tissue interface area. Conclusion: With a larger electrode, both increased cooling and increased electrode-tissue interface area increase volume of resistive heating and lesion depth.

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KW - Electrode size

KW - Electrode-tissue interface area

KW - Lesion size

KW - Radiofrequency

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