Identification of AF Ablation Targets via a Steerable Actuated Catheter

 说明(申请人提供)：房颤(房颤)是最常见的心律失常，患者发病率高，死亡率增加两倍，并增加医疗费用。每年约有20万美国人被诊断为房颤，仅在美国就有数百万人。在大多数病例中，房颤已被证明起源于肺静脉中的触发因素。组织学研究表明，这些触发因素最常位于左房心肌延伸至近端肺静脉。最近，射频消融治疗房颤已成为一种潜在的治疗方法。在房颤消融过程中，利用局部电信号，消融肺静脉内相应的记录电极，间接识别肺静脉内的心肌袖。据报道，成功地隔离肺静脉可以在短期内成功地消除60%-90%的患者的房颤。然而，在较长期的随访评估中，随着肌束逐渐与其余左心房心肌重新连接，复发率达到50%或更高。一种可能的解决方案是使用光学相干断层扫描(OCT)来实现肌束的直接可视化，以指导消融并确认此后治愈的组织坏死。因此，该项目的目标是开发一种诊断仪，它也包括一个离散驱动的可定向机器人导管，带有一个集成了OCT探头的超声微马达，用于径向OCT成像器定位，将可靠地显示肺静脉袖子。此外，通过OCT成像确认(治疗后)肌肉袖子完全坏死的能力将为该程序提供一个非常有用的临床终点，并降低长期治疗失败和肌肉重新连接的风险。因此，在这个项目中，我们将：具体目标1：开发一种离散驱动的可定向机器人导管，带有集成的OCT成像探头和微电机，用于径向OCT成像仪定位，以帮助导航到静脉，以便将OCT成像探头放置在感兴趣区域。此外，导管将能够以多个自由度在3D中移动。具体目标2：建立OCT成像标准，用于在体外绵羊心脏中原位识别心肌和纤维组织以及消融和正常心脏组织。具体目的3：评估机器人导管与集成OCT在识别：a)体外人心脏心房心肌延伸至肺静脉的准确性；b)绵羊心脏组织的急性射频消融(RFA)病变。

 DESCRIPTION (provided by applicant): Atrial fibrillation (AF) is the most common cardiac arrhythmia and has high patient morbidity, increases mortality two-fold, and increases health care costs. Each year, about 200,000 Americans are newly diagnosed with AF with a prevalence of several million in the U.S. alone. In the majority of cases, AF has been shown to originate from triggers in the pulmonary veins. Histological studies have shown that those triggers are most commonly located in extensions of left atrial myocardium into the proximal pulmonary veins. Recently, radiofrequency ablation of AF has been introduced as a potentially curative alternative treatment. During the ablation of AF, those myocardial sleeves inside the pulmonary veins are identified indirectly by using the local electrical signals and then ablating a the corresponding recording electrodes in the pulmonary veins. Successful isolation of the pulmonary veins has been reported to have short-term success of eliminating AF in 60-90% of patients. However, recurrence rates of 50% or more are reported in longer-term follow-up evaluations as the muscular bundles progressively reconnect with the rest of the left atrial myocardium. One possible solution would be to use optical coherence tomography (OCT) to enable a direct visualization of the muscular bundles to guide the ablation and confirm the curative tissue necrosis thereafter. Hence, the goal of this project is to develop a diagnostic too comprising of a discretely actuated steerable robotic catheter with an integrated OCT probe with an ultrasonic micromotor for radial OCT imager positioning that will reliably visualize the pulmonary vein sleeves. Additionally, the ability to confirm complete necrosis of the muscular sleeve (after treatment) through OCT imaging will provide an extremely helpful clinical endpoint to the procedure and reduce the risk of long-term treatment failure and muscular reconnection. Hence, in this project, we will: Specific Aim 1: Develop a discretely actuated steerable robotic catheter with an integrated OCT imaging probe and micromotor for radial OCT imager positioning to aid in navigating to the vein for placement of the OCT imaging probe in the region of interest. Furthermore, the catheter will be able to move in 3D with multiple degrees-of-freedom. Specific Aim 2: Establish OCT imaging criteria for identifying myocardial vs. fibrous tissue and ablated vs. normal cardiac tissue in situ in ex vivo sheep hearts. Specific Aim 3: Evaluate the accuracy of robotic catheter with integrated OCT in identifying: a) atrial myocardial extensions into the pulmonary veins in the ex vivo human heart and b) acute radiofrequency ablation (RFA) lesions in sheep cardiac tissue.