Ablation with an internally irrigated radiofrequency catheter: Learning how to avoid steam pops

Joshua M. Cooper, John L. Sapp, Usha Tedrow, Christine P. Pellegrini, David Robinson, Laurence M. Epstein, William G. Stevenson

Research output: Contribution to journalArticlepeer-review

75 Citations (Scopus)

Abstract

Objectives. The aim of this study was to assess the feasibility of using electrode temperature, impedance, and power to predict and thereby potentially prevent steam pops during cooled radiofrequency (RF) ablation. Background. When myocardial temperature reaches 100°C dur ing RF catheter ablation, steam explosions are seen. Saline-cooled RF ablation reduces temperatures at the electrode-tissue interface, but excessive intramyocardial heating still may occur. Methods. In anesthetized swine, 26 cooled RF applications were made in the right and left atria while observing with intracardiac echocardiography (ICE). Power delivery was increased gradually until a steam explosion was seen or a maximum output of 50 W was reached. Results. ICE identified steam explosions in 21 RF applications. Steam explosions were associated with a large impedance increase, >25 Ω in only three cases, whereas small increases <10 Ω (mean 5.3 ± 2.6 Ω) occurred in 18 cases. Mean electrode temperature at the time of steam explosion was 43.6°C ± 5.3; 18 of 21 explosions occurred when temperature reached ≥40°C. Mean power and impedance drop were similar for applications with and without steam explosions. Five steam explosions were associated with a sudden drop in electrode temperature. Conclusions. Steam explosions are common when cooled electrode temperature exceeds 40°C and are not predictable from power or impedance drop. Small impedance rises and sudden drops in measured electrode temperature indicate possible steam formation. Maintaining cooled electrode temperature <40°C during RF likely will reduce the risk of steam explosions.

Original languageEnglish
Pages (from-to)329-333
Number of pages5
JournalHeart Rhythm
Volume1
Issue number3
DOIs
Publication statusPublished - Sept 2004

Bibliographical note

Funding Information:
Supported by a research grant from Boston Scientific/EP Technologies.David Robinson is an employee of Boston Scientific, Inc.

ASJC Scopus Subject Areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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