title: Feasibility of noncontact intracardiac ultrasound ablation and imaging catheter for treatment of atrial fibrillation.
abstract: Atrial fibrillation (AF) affects 1% of the population and results in a cost of 2.8 billion dollars from hospitalizations alone. Treatments that electrically isolate portions of the atria are clinically effective in curing AF. However, such minimally invasive catheter treatments face difficulties in mechanically positioning the catheter tip and visualizing the anatomy of the region. We propose a noncontact, intracardiac transducer that can ablate tissue and provide rudimentary imaging to guide therapy. Our design consists of a high-power, 20 mm by 2 mm, 128-element, transducer array placed on the side of 7-French catheter. The transducer will be used in imaging mode to locate the atrial wall; then, by focusing at that location, a lesion can be formed. Imaging of previously formed lesions could potentially guide placement of subsequent lesions. Successive rotations of the catheter will potentially enable a contiguous circular lesion to be created around the pulmonary vein. The challenge of intracardiac-sized transducers is achieving high intensities (300-5000 W/cm2) needed to raise the temperature of the tissue above 43 degrees C. In this paper, we demonstrate the feasibility of an intracardiac-sized transducer for treatment of atrial fibrillation. In simulations and proof-of-concept experiments, we show a 37 degrees C temperature rise in the lesion location and demonstrate the possibility of lesion imaging.
authors.affiliation: Stanford University, Department of Electrical Engineering, Stanford, CA, USA. shwong@stanford.edu
authors.forename: Serena H
authors.initials: SH
authors.lastname: Wong
authors.forename: Greig C
authors.initials: GC
authors.lastname: Scott
authors.forename: Steven M
authors.initials: SM
authors.lastname: Conolly
authors.forename: Girish
authors.initials: G
authors.lastname: Narayan
authors.forename: David H
authors.initials: DH
authors.lastname: Liang
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000628:therapy*; D006328:Cardiac Catheterization / Q000295:instrumentation* / Q000379:methods; D017076:Computer-Aided Design; D004452:Echocardiography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000379:methods