Identification of AF Ablation Targets via a Steerable Actuated Catheter

 描述（由申请人提供）：房颤（AF）是最常见的心律失常，患者发病率高，死亡率增加两倍，并增加医疗保健费用。每年，约有20万美国人被新诊断为AF，仅在美国就有数百万人患病。在大多数情况下，AF已被证明起源于肺静脉中的触发。组织学研究表明，这些触发器最常见于左心房心肌向近端肺静脉的延伸。最近，房颤的射频消融术已被引入作为一种潜在的治愈性替代治疗。在房颤消融过程中，通过局部电信号间接识别肺静脉内的心肌袖，然后消融肺静脉内相应的记录电极。据报告，成功隔离肺静脉可在短期内成功消除60-90%的患者的房颤。然而，在长期随访评估中报告了50%或更高的复发率，因为肌束逐渐与左心房心肌的其余部分重新连接。一种可能的解决方案是使用光学相干断层扫描（OCT）来实现肌肉束的直接可视化，以引导消融并在其后确认治疗性组织坏死。因此，本项目的目标是开发一种诊断工具，包括离散驱动的可操纵机器人导管，该导管带有集成OCT探头和超声微电机，用于径向OCT成像仪定位，可可靠地可视化肺静脉袖。此外，通过OCT成像确认肌袖完全坏死（治疗后）的能力将为手术提供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，在本项目中，我们将：具体目标1：开发一种离散驱动的可操纵机器人导管，该导管具有集成的OCT成像探头和微型电机，用于径向OCT成像仪定位，以帮助导航到静脉，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。具体目标二：建立OCT成像标准，用于识别离体绵羊心脏中原位心肌与纤维组织以及消融与正常心脏组织。具体目标3：评价集成OCT的机器人导管在识别：a）离体人类心脏中心房心肌延伸至肺静脉和B）绵羊心脏组织中急性射频消融（RFA）病变方面的准确性。

 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.