Novel Catheter for Treatment of Ventricular Tachycardia

描述(由申请人提供)：在美国每年发生的300,000例心脏性猝死中，一半以上是由缺血性室性心动过速(VT)引起的。植入式心律转复除颤器(ICD)是标准的治疗方法，但它们很昂贵，ICD植入物的总成本接近5万美元，美国每年在这些植入物上花费超过22亿美元。ICD是有效的，但不能治愈接受ICD的患者中，多达一半的患者出现了对除颤器没有反应的新的VT部位，需要额外支付抗心律失常药物的费用。在过去的几年里，有55000个ICD因设计和可靠性问题而被召回。热消融治疗多种室上性心动过速的成功率在90%以上，是ICD植入术的一种有吸引力的替代或辅助治疗方法，但在治疗缺血性室性心动过速方面尚未取得成功。人们普遍认为消融治疗是不成功的，因为它不能治疗引起缺血性室速的大而深的致心律失常灶。我们已经开发出一种方法，能够使用盐水增强射频消融(SERF)来做到这一点。我们通过在射频消融的同时向组织内注射温盐水来治疗室性心动过速。注入的生理盐水流经细胞外空间，传递能量。这使组织的有效导热系数增加了20倍以上。我们使用带有可伸缩电极的可定向SERF消融导管在犬脑梗塞模型中证明SERF消融可以产生足够大的热损伤，足以治疗室性心动过速。即使在存在梗死疤痕的情况下，这些病变也是可靠的透壁的，并且可以放置多个病变来提供阻滞线。我们还证明了这种疗法是安全的，导管符合安全和可靠的要求，并且它是生物相容的。我们建议完成我们的盐水增强射频消融系统的开发，用于治疗缺血性室速。我们将完成我们的系统和导管的设计，并验证它们是否符合医疗安全标准(EN60601-1)、生物兼容性(ISO-10993)，并将灭菌验证至10-6的无菌保证水平(SAL)。我们将在梅奥诊所、洛约拉大学、宾夕法尼亚大学和布里格姆妇女医院的大型动物梗塞模型中进行广泛的临床前生存测试。然后，我们将申请并获得研究设备豁免(IDE)，以进行一项多中心临床试验。公共卫生相关性我们开发消融治疗室性心动过速(VT)与公共健康相关，因为我们正在解决一个日益增长且昂贵的问题，患者接受植入性心律转复除颤器(ICD)来治疗这些潜在的致命心律失常既不能治愈，也不可靠。美国每年花费超过20亿美元放置ICD，一半的患者出现额外的VT，对他们的ICD没有反应。至少，这些患者受到的冲击会严重降低他们的生活质量。在最坏的情况下，患者仍然容易发生心脏性猝死。迫切需要一种有效且廉价的方法来治疗这些患者的室性心动过速。

DESCRIPTION (provided by applicant): Ischemic ventricular tachycardia (VT) is a contributing cause to more than half of the 300,000 sudden cardiac deaths that occur annually in the United States. Implantable cardioverter defibrillators (ICDs) are the standard therapy but they are expensive the total cost of an ICD implant approaches $50,000 and the United States spends more than $2.2B on these implants annually. ICDs are effective, but not curative up to half of the patients who receive ICDs develop new sites of VT that are unresponsive to the defibrillator, requiring them to be put on antiarrhythmia drugs at additional cost. And 55,000 ICDs have been recalled in the last few years for design and reliability problems. Thermal ablation therapy is an attractive alternative or adjunctive therapy to ICD implantation as it has a success rate of more than 90% for many classes of supraventricular tachycardias, but it has not been successful in treating ischemic VT. It is generally agreed that ablation therapy has been unsuccessful because it is not capable of treating the large, deep arrhythmogenic foci that cause ischemic VT. We have developed a method capable of doing so using saline-enhanced radiofrequency (SERF) ablation. We treat VT by injecting warm saline into the tissue simultaneous with RF ablation. The infused saline flows through the extracellular space convecting energy. This increases the effective thermal conductivity of the tissue by a factor of more than 20. We have used our steerable SERF ablation catheter with a retractable electrode to demonstrate in a canine infarct model that SERF ablation creates thermal lesions large enough to treat VT the lesions are reliably transmural, even in the presence of infarct scars, and multiple lesions can be placed to provide a line of block. We have also shown that the therapy is safe, that the catheter meets safety and reliability requirements, and that it is biocompatible. We propose to complete the development of our saline-enhanced radiofrequency (SERF) ablation system for treating ischemic VT. We will complete the design of our system and catheter and validate that they comply with medical safety standards (EN60601-1), biocompatibility (ISO-10993), and validate the sterilization to a sterility assurance level (SAL) of 10-6. We will carry out extensive preclinical survival testing in large-animal infarct models at the Mayo Clinic, Loyola University, The University of Pennsylvania, and the Brigham and Women's Hospital. We will then apply for and obtain an Investigational Device Exemption (IDE) to carry out a multi-center clinical trial. PUBLIC HEALTH RELEVANCE Our development of SERF ablation to treat ventricular tachycardia (VT) is relevant to public health in that we are addressing a growing and expensive problem the implantable cardioverter defibrillators (ICDs) that patients receive to treat these potentially fatal arrhythmias are neither curative nor reliable. The United States spends over $2B annually placing ICDs, and half of the patients develop additional VTs that are unresponsive to their ICD. At minimum the shocks these patients receive severely reduce their quality of life. At worst the patient remains susceptible to sudden cardiac death. An effective and inexpensive method of treating these patients VTs is urgently needed.