Experimental studies with a 9F forward-looking intracardiac imaging and ablation catheter.
OBJECTIVE
The purpose of this study was to develop a high-resolution, near-field-optimized 14-MHz, 24-element broad-bandwidth forward-looking array for integration on a steerable 9F electrophysiology (EP) catheter.


METHODS
Several generations of prototype imaging catheters with bidirectional steering, termed microlinear (ML), were built and tested as integrated catheter designs with EP sensing electrodes near the tip. The wide-bandwidth ultrasound array was mounted on the very tip, equipped with an aperture of only 1.2 by 1.58 mm. The array pulse echo performance was fully simulated, and its construction offered shielding from ablation noise. Both ex vivo and in vivo imaging with a porcine animal model were performed.


RESULTS
The array pulse echo performance was concordant with Krimholtz-Leedom-Matthaei model simulation. Three generations of prototype devices were tested in the right atrium and ventricle in 4 acute pig studies for the following characteristics: (1) image quality, (2) anatomic identification, (3) visualization of other catheter devices, and (4) 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 2 cm, 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.
Stephens
Douglas N
DN
University of California, Davis, California USA.
O'Donnell
Matthew
M
Thomenius
Kai
K
Dentinger
Aaron
A
Wildes
Douglas
D
Chen
Peter
P
Shung
K Kirk
KK
Cannata
Jonathan
J
Khuri-Yakub
Pierre
P
Oralkan
Omer
O
Mahajan
Aman
A
Shivkumar
Kalyanam
K
Sahn
David J
DJ
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D004452:Echocardiography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000601:surgery*; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000601:surgery*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D014159:Transducers