The application of therapeutic ultrasound for the treatment of atrial fibrillation (AF) is investigated. The results of theoretical and experimental investigation of ultrasound ablation catheter are presented. The major components of the catheter are the high power cylindrical piezoelectric element and parabolic balloon reflector. Thermal elevation in the ostia of pulmonary veins is achieved by focusing the ultrasound beam in shape of a torus that transverses the myocardial tissue. High intensity ultrasound heating in the focal zone results in a lesion surrounding the pulmonary veins that creates an electrical conduction blocks and relief from AF symptoms. The success of the ablation procedure largely depends on the correct choice of reflector geometry and ultrasonic power. We present a theoretical model of the catheter’s acoustic field and bioheat transfer modeling of cardiac lesions. The application of an empirically derived relation between lesion formation and acoustic power is shown to correlate with the experimental data. Developed control methods combine the knowledge of theoretical acoustics and the thermal lesion formation simulations with experiment and thereby establish dosimetry that contributes to a safe and effective ultrasound ablation procedure.

中文翻译：

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用于治疗房颤的聚焦超声消融导管形成病变的机制。

研究了治疗性超声在心房颤动 (AF) 治疗中的应用。介绍了超声消融导管的理论和实验研究结果。导管的主要部件是高功率圆柱形压电元件和抛物线球囊反射器。通过将超声波束聚焦成横穿心肌组织的环面形状来实现肺静脉口的热升高。聚焦区中的高强度超声加热会导致肺静脉周围的病变，从而产生电传导阻滞并缓解 AF 症状。消融程序的成功很大程度上取决于反射器几何形状和超声波功率的正确选择。我们提出了导管声场的理论模型和心脏病变的生物传热模型。病变形成和声功率之间的经验导出关系的应用被证明与实验数据相关。开发的控制方法将理论声学知识和热损伤形成模拟与实验相结合，从而建立有助于安全有效超声消融程序的剂量学。