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. 2024 Jun;17(6):e012635.
doi: 10.1161/CIRCEP.123.012635. Epub 2024 May 28.

Can Intracardiac Echocardiography Reduce Steam Pops During Half-Normal Saline Irrigated Radiofrequency Ablation?

Kanae Hasegawa  1   2 , Zachary T Yoneda  1 , Jose R Martines-Parachini  1 , Edward M Powers  1 , Giovanni E Davogustto  1 , Tiffany Y Hu  1 , Kenichi Tokutake  1 , Masaaki Kurata  1 , Travis D Richardson  1 , Jay A Montgomery  1 , Sharon Shen  1 , Juan C Estrada  1 , Pablo J Saavedra  1 , Amy Emerson  1 , Marilyn L Walker  1 , Harikrishna Tandri  1 , Gregory F Michaud  1 , Arvindh N Kanagasundram  1 , William G Stevenson  1
Affiliations

Can Intracardiac Echocardiography Reduce Steam Pops During Half-Normal Saline Irrigated Radiofrequency Ablation?

Kanae Hasegawa et al. Circ Arrhythm Electrophysiol. 2024 Jun.

Abstract

Background: Irrigated radiofrequency ablation with half-normal saline can potentially increase lesion size but may increase the risk of steam pops with the risk of emboli or perforation. We hypothesized that pops would be preceded by intracardiac echocardiography (ICE) findings as well as a large impedance fall.

Methods: In 100 consecutive patients undergoing endocardial ventricular arrhythmia radiofrequency ablation with half-normal saline, we attempted to observe the ablation site with ICE. Radiofrequency ablation power was titrated to a 15 to 20 Ohm impedance fall and could be adjusted for tissue whitening and increasing bubble formation on ICE. Steam pops were defined as audible or a sudden explosion of microbubbles on ICE.

Results: Of 2190 ablation applications in 100 patients (82% cardiomyopathy, 50% sustained ventricular tachycardia), pops occurred during 43 (2.0%) applications. Sites with pops had greater impedance decreases of 18 [14, 21]% versus 13 [10, 17]% (P<0.001). ICE visualized 1308 (59.7%) radiofrequency sites, and fewer pops occurred when ICE visualized the radiofrequency ablation site (1.4%) compared with without ICE visualization (2.8%; P=0.016). Of the 18 ICE-visible pops, 7 (39%) were silent but recognized as an explosion of bubbles on ICE. With ICE, 89% of pops were preceded by either tissue whitening or a sudden increase in bubbles. In a multivariable model, tissue whitening and a sudden increase in bubbles were associated with steam pops (odds ratio, 7.186; P=0.004, and odds ratio, 29.93; P<0.001, respectively), independent of impedance fall and power. There were no pericardial effusions or embolic events with steam pops.

Conclusions: Steam pops occurred in 2% of half-normal saline radiofrequency applications titrated to an impedance fall and are likely under-recognized without ICE. On ICE, steam pops are usually preceded by tissue whitening or a sudden increase in bubble formation, which can potentially be used to adjust radiofrequency application to help reduce pops.

Keywords: arrhythmias, cardiac; echocardiography; radiofrequency ablation; saline solution; steam.

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Conflict of interest statement

Disclosures Dr Stevenson received an honoraria from Boston Scientific, Abbott, Johnson and Johnson, Medtronic, and Biotronik, and co-holder of a patent for irrigated needle ablation that is consigned to Brigham Hospital. Dr Kanagasundram received speaking honoraria from Abbott and Johnson and Johnson. Dr Michaud received an honoraria/consulting from Boston Scientific, Abbott, Biosense Webster, GE, and Mediasphere, and consultant for Boston Scientific, Abbott, Johnson and Johnson, and GE. Dr Richardson is a consultant for Medtronic, Johnson and Johnson, and Philips, and received research funding from Medtronic and Abbott. The other authors report no conflicts.

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