Abstract 16754: The Impact of Left Atrial Ablation Procedure and Strategy on Microemboli Formation During Irrigated RF Catheter Ablation in an in vivo Model
Background: Microemboli during catheter ablation may cause asymptomatic cerebral emboli. However, there is limited characterization of microemboli formation using open-irrigated radiofrequency (RF) catheters. It is also unknown which part of the procedure is most strongly related to this occurrence.
Methods: Catheter ablation was performed in the left atrium of 19 pigs. Microbubble volume (MBV) and microparticles (clot/tissue) were monitored using an ultrasonic bubble counter and blood filter in an extracorporeal circulation loop. Doppler signals of the carotid artery were monitored for microemboli signals (MES). Intracardiac echography images were also acquired. Ablation was performed using open-irrigated RF catheters. Point-by-point (30 or 60 sec) and drag ablations (240 sec) using 30W/50W were performed. ACT was maintained at 350-400 sec.
Results: In total, 208 RF applications (190 point-by-point, 18 drag ablations) and 203 sheath/catheter manipulations (transseptal puncture, sheath flush, catheter insertion, PV angiography, and sheath exchange) were analyzed. Steam pops were seen in 30/208 applications. Excluding steam pops, 50W ablation produced higher MBV and more MES than 30W ablation. Drag ablation produced higher MBV and more MES than point-by-point ablation. Ablations with steam pops produced much higher MBV and more MES than ablation without steam pops. During sheath/catheter manipulation, fast sheath flush (injection speed: 8 cc saline/1 sec) produced the highest MBV (100 times higher than slow sheath flush [8 cc saline/5 sec]) and MES. A total of 28 microparticle events were seen. Only 1 microparticle was observed before RF application. Fifteen microparticle events were seen after 50W point-by-point ablations, 9 were seen after drag ablation.
Conclusion: Formation of microbubbles was greatest during fast sheath flush and steam pops, while high power RF application, drag ablation, and steam pops produced most of the microparticles.
Author Disclosures: M. Takami: None. H. Lehmann: Research Grant; Significant; American Heart Association. K.D. Parker: None. S.B. Johnson: None. D.L. Packer: Research Grant; Modest; Endosense, Siemens Acuson, EP Advocate, U of Minnesota Partnership for Biotechnology and Medical Genomics, CardioFocus, Hansen Medical, Thermedical. Consultant/Advisory Board; Modest; Abiomed $0, Biosense Webster $0, Boston Scientific $0, CardioDX $0, CardioFocus $0, CardioInsight $0, InfoBionics $0, Johnson & Johnson $0, Medtronic/CryoCath $0, Sanofi-Aventis $0, Siemens $0, St. Jude Medical $0, OrthoMcNeill $0. Other; Modest; Royalty Blackwell Publishing, Oxford Publishing, Oxford Royalty. Research Grant; Significant; Biosense Webster, EpiEP, Medtronic, NIH, AHA Fellow Grant, Boston Scientific, St. Jude Medical. Other; Significant; Royalty St. Jude Medical.
- © 2014 by American Heart Association, Inc.