Abstract 9413: A Feasibility Study of Non-Invasive Ablation of Ventricular Tachycardia Using High-Intensity Focused Ultrasound
Introduction: Conventional catheter ablation of ventricular tachycardia (VT) is limited in part by its invasiveness and associated complications, particularly when an epicardial approach is needed. This study evaluated the feasibility of targeted ablation of cardiac tissues using high-intensity focused ultrasound (HIFU) as a potential means for non-invasive VT ablation.
Methods & Results: Ablation of ventricular myocardium was performed in anesthetized closed-chest dogs using a HIFU therapeutic system that is being used clinically for ablation of human solid tumors. The animal was placed onto the HIFU system with its left chest immersed in a tank filled with specially treated water. Ventricular pacing using a quadripolar catheter via the internal carotid artery was performed at a rate slightly higher than intrinsic sinus rate to mimic VT. The myocardium at the tip of the pacing catheter (Figure 1) was targeted for ablation (400 watts for 2-4 s). Ablation end-point was loss of ventricular capture at twice pacing threshold. In 5 separate preparations, pacing could be terminated successfully (Figure 2). No subsequent capture was seen at 5 times baseline pacing threshold but capture could be obtained at different locations using the same pacing catheter. Both transmural and localized lesions could be created in a controlled fashion without evident injury to the skin, lung, or pericardium on postmortem examination.
Conclusion: This pilot study suggests that HIFU is potentially useful for non-invasive ablation of targeted, localized myocardial tissue; and may be applicable for VT ablation, particularly those of intramyocardial / epicardial origin.
- © 2013 by American Heart Association, Inc.