1004-55 The Utility of a New Integrated High Resolution Intracardiac Ultrasound/Ablation System in a Canine Model

To examine the utility of ultrasound visualization for guiding ablation of cardiac tissue, an intracardiac ultrasound cardioscope incorporating a catheter visualization/delivery system into the imaging head of the device was examined in 16 dogs. The ultrasound ablation probe (Acuson 7.5MHz/8mm) was introduced via the right external jugular vein into the right atrium/ventricle. Long axis imaging from the probe to a depth exceeding 7cm enabled high resolution visualization extending from the pulmonary veins, through the level of each cardiac valve to the left ventricular apex. Ablation catheters along with tip electrodes were readily visualized, allowing their non-fluoroscopic passage across the aortic, mitral, and tricuspid valves for ventricular mapping and ablation. Specific parallel or perpendicular catheter tip/tissue orientation was readily documented in each case, as was the catheter tip/tissue contact with the use of standard and basket array catheters. For ablation of right heart structures, an ablation catheter port incorporated into the imaging head facilitated direct visualization of the catheter-tissue interface and evolving tissue injury and thrombus formation during ablation. Using non-contrast techniques, ablation lesions in the left ventricle could be measured and catheter-related clot formation monitored. Perfusion catheter tip flow used to ameliorate the ablation-related impedance rise was also documented by color flow techniques. These studies demonstrate the facilitation of ablation catheter positioning and catheter tip/tissue orientation and contact monitoring with a high resolution intracardiac ultrasound system. This study strongly supports the concept of incorporating ultrasound and ablation catheter deployment into a single cardioscopy system