Feasibility of noncontact intracardiac ultrasound ablation and imaging catheter for treatment of atrial fibrillation

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2006-12, Vol.53 (12), p.2394-2405
• Main Authors: Wong, S.H., Scott, G.C., Conolly, S.M., Narayan, G., Liang, D.H.
• Format: Article
• Language: English
• Subjects: Ablation; Atrial fibrillation; Atrial Fibrillation - diagnostic imaging; Atrial Fibrillation - therapy; Biological and medical sciences; Cardiac Catheterization - instrumentation; Cardiac Catheterization - methods; Catheters; Computer-Aided Design; Costs; Curing; Echocardiography - instrumentation; Echocardiography - methods; Equipment Design; Equipment Failure Analysis; Feasibility; Feasibility Studies; Fibrillation; Humans; Imaging; Investigative techniques, diagnostic techniques (general aspects); Lesions; Medical sciences; Minimally invasive surgery; Miscellaneous. Technology; Position (location); Reproducibility of Results; Sensitivity and Specificity; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Temperature; Transducers; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonic Therapy - instrumentation; Ultrasonic Therapy - methods; Ultrasonography, Interventional - instrumentation; Ultrasonography, Interventional - methods; Visualization
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2006.188

Atrial fibrillation (AF) affects 1% of the population and results in a cost of 2.8 billion 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/cm 2 ) needed to raise the temperature of the tissue above 43degC. 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 37degC temperature rise in the lesion location and demonstrate the possibility of lesion imaging