Author + information
- Received June 25, 2017
- Revision received September 12, 2017
- Accepted October 4, 2017
- Published online April 16, 2018.
- Duy T. Nguyen, MD∗ (, )
- Matthew Zipse, MD,
- Ryan T. Borne, MD,
- Lijun Zheng, MS,
- Wendy S. Tzou, MD and
- William H. Sauer, MD
- Section of Cardiac Electrophysiology, Division of Cardiology, University of Colorado, Aurora, Colorado
- ↵∗Address for correspondence:
Dr. Duy T. Nguyen, Section of Cardiac Electrophysiology, Division of Cardiology, University of Colorado, B-132, Leprino Building, 12401 East 17th Avenue, Aurora, Colorado 80045.
Objectives Given a paucity of data, the aim of this study was to define predictors of steam pops (SPs) during open-irrigated radiofrequency ablation (RFA).
Background SPs during RFA can lead to dire consequences, including perforation and stroke.
Methods In an ex vivo bovine myocardium model, open-irrigated RFA was applied at 50 W for 60 s; intracardiac echocardiographic images for RFA with and without SPs was compared. Using an in vivo porcine model, open-irrigated RFA was applied at 50 W for 60 s, and RFA parameters of SPs were analyzed. A retrospective analysis was performed of recorded SPs during clinical ablation procedures over a 1-year period.
Results For RFA SPs, there was 32% greater intracardiac echocardiographic tissue echogenicity than for RFA without SPs (p < 0.001). In addition, RFA SPs had more rapid increases of tissue echogenicity, particularly in the last 5 s before SPs. Compared with RFA without SPs, RFA SPs had larger impedance reductions (33.0 ± 16.0 Ω vs. 23.0 ± 10.8 Ω; p = 0.032). SPs were also associated with more rapid initial impedance reduction (1.40 Ω/s vs. 0.38 Ω/s for RFA without SPs; p = 0.001). Clinical SPs during ablation procedures had a significantly faster impedance reduction during the first 5 s of ablation compared with matched control ablations (15.7 ± 6.7 Ω vs. 8.1 ± 4.7 Ω; p < 0.0001).
Conclusions Certain echocardiographic and biophysical parameters during open-irrigated RFA are associated with increased SP risks. These include greater tissue echogenicity, larger total impedance reduction, rapid rate of initial impedance reduction, and rapid increase in tissue echogenicity.
Drs. Sauer and Nguyen have received significant research grants from Biosense Webster and CardioNXT; and educational grants from Biosense Webster, Boston Scientific, and Medtronic; and they have a provisional patent on partially insulated focused catheter ablation; and have nonpublic equity interests and stock options in CardioNXT. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
All authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Received June 25, 2017.
- Revision received September 12, 2017.
- Accepted October 4, 2017.
- 2018 American College of Cardiology Foundation
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