An anatomic approach to prevention of atrial fibrillation: Pulmonary vein isolation with through-the-balloon ultrasound ablation (TTB-USA)

Our current understanding is that atrial fibrillation (AF) is initiated mos t often by a focal trigger from the orifice of or within one of the pulmona ry veins. Though mapping and ablation of these triggers appears to be curat ive in most patients with paroxysmal AF, there are a number of limitations to ablating focal triggers via mapping and ablating the earliest site of ac tivation with a "point" radiofrequency lesion. One way to circumvent thesen limitations is an anatomically-guided ablative approach, By electrically i solating one or more pulmonary veins from the left atrium with a circumfere ntial lesion, firing from within those veins would be unable to reach the b ody of the atrium, and thus could not trigger atrial fibrillation. We have developed a novel over-the-wire catheter design which integrates a cylindri cal ultrasound transducer within a saline filled balloon, termed TTB-USA (t hrough-the-balloon ultrasound ablation) in order to produce narrow circumfe rential zones of hyperthermic tissue death at the pulmonary vein ostia. Ani mal studies show great promise, and clinical trials will begin soon.