Novel 3D Catheter Tracking System for Intracardiac Navigation

描述(由申请人提供)：拟议的研究项目将需要开发和初步测试一种用于心脏内导航的新型3D导管跟踪系统。该项目的长期目标是开发一种自给自足的跟踪机制，可以用于任何临床目的，需要对心脏内的导管进行准确的3D操作。目前设想的第一个商业应用将是一种系统，旨在生成心脏电活动的3D地图，并准确指导心律失常的治疗(例如，射频消融)。在过去的几十年里，心律失常的发生率和流行率出现了爆炸性增长，这反映了已知的触发和持续心律异常的各种形式的心脏病的惊人增长。仅房颤一项就已达到流行程度，估计目前约有230万美国人受到影响，到2050年将有约560万人受到影响。此外，40岁时发生房颤的终生风险为22-24%，这种情况与死亡率增加两倍有关。传统的治疗方式，即药物治疗和心内直视手术，已经被发现不能满足越来越多的患者，要么是因为疗效差，要么是因为副作用，或者仅仅是因为外科手术的侵入性。专门的经皮导管的出现和其他使能技术的发展共同提高了微创治疗程序的安全性和有效性。在过去十年中增长了10倍以上，基于导管的手术已经成为有症状患者的首选干预模式。心律异常是一项重大的治疗挑战，因为它们往往是由心脏的特定区域选择性地触发和永久存在的，这些区域往往在患者之间高度可变。由于大多数手术采用心内膜入路，有效的治疗依赖于复杂的3D心内膜表面上异常组织的可靠定位和准确地将消融能量输送到罪犯部位。随着心脏电生理学家进行的基于导管的手术的数量不断增加，对准确可靠的导管跟踪系统的需求变得更加明显。为了响应这种新出现的需求，已经开发了几种系统来促进导管介导的心内膜表面的协商。不幸的是，这些系统都受到显著限制的困扰，包括跟踪失真和对呼吸和其他运动伪影的不充分校正。不准确的导管追踪的潜在后果包括消融正常的心脏组织、穿孔、复发的重复手术以及增加手术和X光曝光时间。因此，毫无疑问，在改善经皮手术的结果方面，更准确的追踪仍然是一个重要的未得到满足的需求。拟议的节律系统构成了下一代技术，该技术的独特架构为运动伪影提供了卓越的补偿。该系统结合其开放的平台架构和对实地不均匀的准确实时校正，将解决现有系统的所有缺点，并提供出色的跟踪精度。通过改善基于导管的手术的安全性和长期成功，心律失常系统可能对患者护理质量产生深远影响，并成为消融手术以及未来更多心脏应用的主要3D跟踪工具。在先前进行的虚拟模拟之后，拟议项目的第一阶段将包括开发一个工作样机，其中包括一个跟踪导管、相关硬件(放大器和过滤器)以及一个运行可视化模块和专有算法的工作站。一旦投入使用，该系统将使用模拟血液和心脏周围结构的电特性的台式体模模型进行测试和改进。具体地说，第一阶段将有以下目标：(1)开发能够跟踪体外试验室内多个电极的3D位置的原型系统。(2)测量电极导管浸泡在均匀电导率介质中时的体外跟踪精度。(3)采用参比电极，引入运动，对导管浸入非均匀介质时的体外跟踪精度进行量化。当具体目标#3结束时，该系统在测量位于跟踪导管50 mm内的两个被跟踪电极(已知相距20 mm)之间的距离时，可以显示出小于2 mm的误差。在成功完成工作台验证后，第二阶段将开始包括大型动物研究。公共卫生相关性：心律失常困扰着越来越多的患者，仅在美国估计就有600万到1000万人。微创手术，如导管消融，正迅速成为消除心律失常和恢复正常心跳的首选方法。拟议的项目旨在开发下一代技术，当导管在心腔内漫游时，在3D空间中更准确地定位导管，以提高治疗过程的安全性和有效性。

DESCRIPTION (provided by applicant): The proposed research project will entail the development and initial testing of a novel 3D catheter tracking system for intra-cardiac navigation. The long-term objective of the project is to develop a self-contained tracking mechanism that could be used for any clinical purpose requiring accurate 3D manipulation of catheters inside the heart. The first commercial application currently envisioned would be a system designed to generate 3D maps of the heart's electrical activity and accurately guide the treatment (e.g., radiofrequency ablation) of cardiac arrhythmias. The incidence and prevalence of cardiac arrhythmias has seen explosive growth in the last few decades, mirroring an alarming increase in all forms of heart disease known to trigger and perpetuate rhythm abnormalities. Atrial fibrillation alone has reached epidemic proportions, estimated to currently afflict ~2.3 million Americans and ~5.6 million by 2050. Moreover, the lifetime risk of atrial fibrillation at age 40 is 22-24% and the condition is associated with a two-fold increase in mortality. Traditional treatment modalities, namely drug therapy and open heart surgery, have been found to be inadequate for a growing number of patients, either because of poor efficacy, side effects, or the mere invasiveness of surgical procedures. The advent of specialized percutaneous catheters and the development of other enabling technologies have collectively led to an improvement in the safety and efficacy of minimally-invasive curative procedures. Having grown more than 10-fold in the last decade, catheter-based procedures have become the preferred mode of intervention in symptomatic patients. Cardiac rhythm abnormalities present a major treatment challenge, as they are often selectively triggered and perpetuated by specific areas of the heart that tend to be highly variable between patients. Since most procedures utilize an endocardial approach, effective therapy depends on reliable localization of the aberrant tissue on the complex 3D endocardial surface and the accurate delivery of ablative energy to culprit sites. As the number of catheter-based procedures performed by cardiac electrophysiologists continues to grow, the need for an accurate and reliable catheter tracking system becomes even more apparent. In response to this emerging need, several systems have been developed to facilitate catheter-mediated negotiation of the endocardial surface. Unfortunately, these systems are all plagued by significant limitations, including tracking distortions and inadequate correction for respiration and other motion artifacts. The potential consequences of inaccurate catheter tracking include ablation of electrically normal cardiac tissue, perforation, repeat procedures for recurrence, and increased procedure and x-ray exposure times. Therefore, there is no doubt that more accurate tracking remains a significant unmet need in improving the outcome of percutaneous procedures. The proposed Rhythmia system constitutes next-generation technology that is uniquely architected to provide superior compensation for motion artifacts. Combined with its open platform architecture and accurate real- time correction of field inhomogeneity, the system would address all the shortcomings of existing systems and provide excellent tracking accuracy. By improving the safety profile and long-term success of catheter-based procedures, the Rhythmia system could have a profound impact on the quality of patient care and become the primary 3D tracking tool for ablation procedures as well as additional future cardiac applications. On the heels of previously performed virtual simulations, Phase I of the proposed project will include the development of a working prototype comprising of a tracking catheter, relevant hardware (amplifiers and filters), and a workstation running a visualization module and proprietary algorithms. Once operational, the system would be tested and improved using bench-top phantom models mimicking the electrical properties of blood and structures surrounding the heart. Specifically, Phase I will have the following aims: (1) Develop a prototype system that would be able to track the 3D location of multiple electrodes within an ex-vivo test chamber. (2) Quantify tracking accuracy ex vivo when electrode-bearing catheters are immersed and surrounded by a medium of homogeneous conductivity. (3) Quantify tracking accuracy ex vivo when catheters are immersed in an inhomogeneous medium, reference electrodes are employed, and motion is introduced. Feasibility will have been demonstrated when at the end of Specific Aim #3, the system can demonstrate sub- 2mm error in measuring the distance between 2 tracked electrodes (known to be 20mm apart) located within 50mm of the tracking catheter. Upon successful completion of bench-top validation, Phase II would be commenced comprising of large animal studies. PUBLIC HEALTH RELEVANCE: Cardiac rhythm abnormalities afflict a growing number of patients, with estimates ranging from 6 to 10 million people in the US alone. Minimally invasive procedures, such as catheter ablation, are quickly emerging as the preferred approach to eliminate cardiac arrhythmias and restore normal heart beat. The proposed project looks to develop next-generation technology for more accurately localizing catheters in 3D space as they are roving within the heart chambers in order to improve both the safety and effectiveness of therapeutic procedures.