Computer-Aided Delivery of High-Intensity Focused Ultrasound (HIFU) for Creation of an Atrial Septal Defect in Vivo

In recent years, several fetal cardiac malformations have been increasingly treated before birth with gradually improved outcome, although the technique is still demanding and invasive. We newly developed a computer-aided system for energy delivery of high-intensity focused ultrasound (HIFU) to correct cardiac morphologic abnormalities in vivomuch less invasively. The HIFU system could be controlled in real-time by a computer-based analysis of 2D-sonographic left ventricular images for optimal triggering off HIFU. Using beating heart of two anesthetized adult rabbits, the system successfully achieved a non-touch gross ablation of the atrial septum in one animal, and in the other HIFU energy was inadvertently mistargeted on the posterior wall of the left atrium with a resultant small transmural opening. We believe that the HIFU system will be introduced with pinpoint accuracy to minimally invasive treatment of fetal cardiac abnormalities that have intact or highly restrictive atrial septum.