The Feasibility of Transesophageal Cardiac Ablation by Focused Ultrasound

摘要

Atrial fibrillation (AF) is the most common arrhythmia, affecting over 2.2 million Americans. One effective treatment is cardiac ablation, which shows a high rate of success in treating paroxysmal AF. Focused ultrasound has gained interest for thermal ablation for decades due to its noninvasive characteristics. Based on the simulation results of transducer arrays, current transesophageal medical devices, and the throat anatomy, we have designed, fabricated, and tested a focused ultrasound applicator that can be inserted into the esophagus for incision-less cardiac ablation. The overall goal is to bring this applicator as closely as possible to the heart in order to effectively deliver ultrasound energy, and create electrically isolating lesions in myocardial tissue, which replicate the currently used Maze procedure. The transducer design is a two-dimensional sparse phased array with flat tapered elements operating at a frequency of 1.6 MHz. This array uses 64 active elements spatially sampled from 195 rectangular elements. Its probe head housing is 19 mm in diameter and incorporates an acoustic window. A prototype applicator has been successfully tested ex vivo using fresh porcine myocardial tissue. The results demonstrated a potential applicability of an ultrasound applicator to transesophageal cardiac surgery in AF treatment.