High Frequency Ultrasound Arrays for Cardiac Imaging

描述（由申请人提供）：心房颤动和扑动等心律失常影响约 240 万美国人，仅美国每年就有约 160,000 个新病例。由于在心血管系统内引导基于导管的诊断和治疗设备存在困难，治疗心律失常的电生理 (EP) 和射频 (RF) 消融手术是最耗时、最详细的手术之一。尽管透视仍然是黄金标准成像工具，但人们普遍认识到，随着手术时间更长、更具挑战性，迫切需要新的、更有效的实时空间测绘工具来改善临床结果并减少患者目前暴露的荧光透视辐射剂量。此外，《循环》杂志最近对消融方法的一项综述指出，“射频是所使用的主要能源，但仍然不足以确保病变的连续性和持久性，同时不会导致手术时间和并发症的增加不可接受。需要新的、有效的和安全的替代能源来实现针对所有形式的 AF（心房颤动）的单一、广泛适用的治愈手术的最终目标。”我们的项目旨在解决老龄化人口中的这一主要心血管问题，这与国家心肺血液研究所的使命相一致。我们与学术机构和公司的临床医生、电生理学家和工程师合作，提议在可操纵电生理导管上开发新型高度小型化和独特的心内成像设备，该设备可以提供 2D 和 3D 超声成像，将成像、病变表征和治疗完全集成在同一导管设备内。 我们还建议：将这些设备的消融能力从射频能量扩展到更新的方法，包括高强度聚焦超声 (HIFU) 和激光消融，这两种方法都可以产生更集中和离散的连续病变。我们还将开发并提供在线功能，以便快速评估 EP 消融手术的结果和有效性。这些方法包括评估组织加热的热应变成像和激光声学组织表征等方法，以及定义心室电解剖图的 3D 融合显示器上显示的消融组织改变的机械特性的超声方法以及心律的正常和异常传导的传播。我们提议的项目建立在我们前 5 年的资金基础上，结合了最新、最先进和小型的超声换能器技术以及布线和连接方法，能够将成像和评估与直接能量输送集成在一起，以便在同一基于 EP 导管的消融设备中进行消融。我们期望我们的工作成果能够提高这些复杂治疗策略的功效和可用性，同时减少手术时间、辐射暴露和成本。 公共卫生相关性：严重的心律异常，例如被称为心房颤动的快速且不规则的心律，通常需要通过经导管消融手术进行治疗。这些漫长而复杂的手术的成功率参差不齐，并且异常节律发作经常复发。我们的临床医生和工程师合作伙伴计划开发新的基于导管的方法，通过整合心腔内的能量输送和超声成像来进行消融，目标是缩短这些手术的持续时间，最大限度地减少患者和医生的辐射暴露，并改善消融效果。

DESCRIPTION (provided by applicant): Cardiac dysrhythmias such as atrial fibrillation and flutter affect about 2.4 million Americans, with approximately 160,000 new cases in the US alone every year. Electrophysiological (EP) and radiofrequency (RF) ablation procedures to treat cardiac arrhythmias are among the most prolonged and detailed due to the difficulties in the guidance of catheter based diagnostic and therapeutic devices within the cardiovascular system. Although fluoroscopy is still the gold standard imaging tool, it is well recognized that with longer and more challenging procedures, new and more effective real time spatial mapping tools are vitally needed to improve clinical outcomes and to reduce the fluoroscopic radiation doses to which patients are currently exposed. Also a recent review of ablation methods in Circulation stated that "Radiofrequency is the dominant energy source used but remains inadequate to ensure lesion continuity and permanence without an unacceptable increase in procedural time and complications. New, effective, and safe alternative energy sources are needed to achieve the ultimate goal of a single, widely applicable, curative procedure for all forms of AF (atrial fibrillation)." Our project is targeted at this major cardiovascular problem in our aging population concordant with the mission of the National Heart, Lung, and Blood Institute. Our Partnership of clinicians, electrophysiologists and engineers from academic institutions and companies is proposing to develop new highly miniaturized and unique intracardiac imaging devices on steerable electrophysiology catheters which can provide 2D and 3D ultrasound imaging to fully integrate imaging, lesion characterization and therapy within the same catheter devices. We also propose: to expand the capabilities for ablation with these devices from RF energy to newer methods including High Intensity Focused Ultrasound (HIFU) and laser ablation both of which can create more focused and discrete continuous lesions. We will also develop and provide on-line capabilities to allow rapid evaluation of the results and effectiveness of EP ablation procedures. These include methods such as thermal strain imaging to assess tissue heating and laser acoustic tissue characterization and ultrasound methods for defining altered mechanical properties of ablated tissue displayed on 3D fusion displays of electroanatomical mapping of the chambers of the heart and the propagation of normal and abnormal conduction of cardiac rhythms. Our proposed project builds on our first 5 years of funding combining the newest most advanced and miniaturized ultrasound transducer technologies and cabling and connection methods, with the ability to integrate imaging and assessment with direct energy delivery for ablation within the same EP catheter-based ablation devices. It is our expectation that the results of our work can improve the efficacy and availability of these complex treatment strategies while reducing procedure duration, radiation exposure and cost. PUBLIC HEALTH RELEVANCE: Serious abnormalities of cardiac rhythms, such as the rapid and irregular rhythms referred to as atrial fibrillation, often require treatment by trans-catheter ablation procedures. These long and complicated procedures have variable success rates and the abnormal rhythm episodes often recur. Our Partnership of clinicians and engineers is planning to develop new catheter-based methods for performing ablation with integration of energy delivery and ultrasound imaging from inside the heart chambers, with the goal of reducing the duration of these procedures, minimizing radiation exposure to the patient and the physician and improving the results of ablation.