title: Feasibility of near real-time lesion assessment during radiofrequency catheter ablation in humans using acoustic radiation force impulse imaging.
abstract: BACKGROUND
  Visual confirmation of radiofrequency ablation (RFA) lesions during clinical cardiac ablation procedures could improve procedure efficacy, safety, and efficiency. It was previously shown that acoustic radiation force impulse (ARFI) imaging can identify RFA lesions in vitro and in vivo in an animal model. This is the "first-in-human" feasibility demonstration of intracardiac ARFI imaging of RFA lesions in patients undergoing catheter ablation for atrial flutter (AFL) or atrial fibrillation (AF).
  
  
  RESULTS
  Patients scheduled for right atrial (RA) ablation for AFL or left atrial (LA) ablation for drug refractory AF were eligible for imaging. Diastole-gated intracardiac ARFI images were acquired using one of two equipment configurations: (1) a Siemens ACUSON S2000™ ultrasound scanner and 8/10Fr AcuNav™ ultrasound catheter, or (2) a CARTO 3™ integrated Siemens SC2000™ and 10Fr SoundStar™ ultrasound catheter. A total of 11 patients (AFL = 3; AF = 8) were imaged. ARFI images were acquired of ablation target regions, including the RA cavotricuspid isthmus (CTI), and the LA roof, pulmonary vein ostia, posterior wall, posterior mitral valve annulus, and the ridge between the pulmonary vein and LA appendage. ARFI images revealed increased relative myocardial stiffness at ablation catheter contact sites after RFA and at anatomical mapping-tagged RFA treatment sites.
  
  
  CONCLUSIONS
  ARFI images from a pilot group of patients undergoing catheter ablation for AFL and AF demonstrate the ability of this technique to identify intra-procedure RFA lesion formation. The results encourage further refinement of ARFI imaging clinical tools and continued investigation in larger clinical trials.
authors.affiliation: Duke Center for Atrial Fibrillation, Duke University Medical Center, North Carolina, USA; Division of Cardiovascular Medicine, Cardiac Electrophysiology Section, Duke University, North Carolina, USA.
authors.forename: Tristram D
authors.initials: TD
authors.lastname: Bahnson
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Eyerly
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hollender
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Doherty
authors.forename: Young-Joong
authors.initials: YJ
authors.lastname: Kim
authors.forename: Gregg E
authors.initials: GE
authors.lastname: Trahey
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Wolf
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000601:surgery*; D013504:Cardiovascular Surgical Procedures / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D003199:Computer Systems; D004452:Echocardiography / Q000379:methods; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome
keywords: acoustic radiation force impulse imaging; atrial fibrillation; atrial flutter; electroanatomical mapping; intracardiac echocardiography; lesion assessment; transcatheter radiofrequency ablation