David E. Francischelli

The Feasibility of Transesophageal Cardiac Ablation by Focused Ultrasound

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 incisionless 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 rect...

In Vivo Evaluations of a Phased Ultrasound Array for Transesophageal Cardiac Ablation

Atrial fibrillation is one of the most common arrhythmias that affects over 2.2 million Americans each year. Catheter ablation, one of the effective treatments, has shown high rate of success in treating paroxysmal atrial fibrillation. Currently, radiofrequency which is being used for catheter ablation is an invasive procedure. Measurable morbidity and significant costs and time are associated with this modality of treatment of permanent or persistent atrial fibrillation. In order to address these issues, a transesophageal ultrasound applicator for noninvasive cardiac ablation was designed, developed and evaluated. The ultrasound energy delivered by the phased array was used to create a lesion in the myocardial tissue. Various factors, simulation results of transducer arrays, current transesophageal medical devices, and throat anatomy, were considered while designing a phased ultrasound transducer that can be inserted into the esophagus. For this research, a two‐dimensional sparse phased array with flat t...