Sinelnikov Y D, Fjield T, Sapozhnikov O A
ProRhythm, 105 Comac Street, Ronkonkoma, NY 11779, USA.
Acoust Phys. 2009 Jul 21;55(4-5):647-656. doi: 10.1134/S1063771009040216.
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 rigorous dosimetry that contributes to a safe and effective ultrasound ablation procedure.
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。该导管的主要部件是高功率圆柱形压电元件和抛物线形球囊反射器。通过将超声束聚焦成环形，使其穿过心肌组织，从而实现肺静脉口处的温度升高。聚焦区内的高强度超声加热会在肺静脉周围形成一个病变，产生电传导阻滞并缓解房颤症状。消融手术的成功很大程度上取决于反射器几何形状和超声功率的正确选择。我们提出了导管声场的理论模型以及心脏病变的生物热传递模型。结果表明，应用根据经验得出的病变形成与声功率之间的关系与实验数据相关。所开发的控制方法将理论声学知识、热损伤形成模拟与实验相结合，从而建立严格的剂量测定法，有助于实现安全有效的超声消融手术。
