Experimental Studies with a 9 French Forward-Looking Intracardiac Imaging and Ablation Catheter

Objective—To develop a high resolution, near field optimized 14 MHz 24-element broad bandwidth forward-looking array for integration on a steerable 9 French (Fr) electrophysiology (EP) catheter. Methods—Several generations of prototype imaging catheters with bi-directional steering, termed the Micro-Linear (ML), have been built and tested as an integrated catheter design with EP sensing electrodes near the tip. The wide bandwidth ultrasound array is mounted on the very tip, equipped with an aperture of only 1.2 mm by 1.58 mm. The array pulse echo performance has been fully simulated and its construction offers shielding from ablation noise. Both ex-vivo and in-vivo imaging with a porcine animal model were performed. Results—The array pulse-echo performance is concordant with KLM simulation. Three generations of prototype devices were tested in four acute pig studies in the right atrium and ventricle for a) image quality, b) anatomic identification, c) visualization of other catheter devices, and d) for a mechanism for stabilization when imaging ablation. The ML catheter is capable of both low artifact ablation imaging on a standard clinical imaging system and high frame rate myocardial wall strain rate imaging for detecting changes in cardiac mechanics associated with ablation. Conclusions—The imaging resolution performance of this very small array device, together with its penetration beyond 2cm, is excellent considering its very small array aperture. The forward looking intracardiac catheter has been adapted to work easily on an existing commercial imaging platform with very minor software modifications. Address for Correspondence: David J. Sahn, MD, L608, Pediatric Cardiology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, Phone: (503) 494–2190;, Fax: (503) 494–2190, sahnd@ohsu.edu. NIH Public Access Author Manuscript J Ultrasound Med. Author manuscript; available in PMC 2009 September 25. Published in final edited form as: J Ultrasound Med. 2009 February ; 28(2): 207–215. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript