LASER CATHETER FOR ABLATION OF VENTRICULAR TACHYCARDIA

室性心动过速（VT）是一种心律失常的特点是异常高的心室收缩率。在室性心动过速期间，心室在每次收缩前不能充满足量的血液，常常导致头晕、意识丧失或心脏骤停。导管消融已被证明是治疗许多心律失常的有效手段，但目前的方法不能凝固心肌中部或心外膜下区域的组织，而这些区域往往是引起室性心动过速的病灶的起源。在这个第一阶段的研究中，我们建议开发和测试一种新型的冷却尖端激光消融导管，用于凝固引起室性心动过速的心肌。这种新型设计包括一个专有的光纤传输系统，该系统包含在冷却尖端内，可以将热能扩散到心肌的更深层，同时防止对心内膜表面的损伤。其他功能将允许实时监测在治疗过程中的心律失常部位的电活动与激光。最后，使用廉价的低功率二极管激光器作为光源，将使治疗成为更实用的临床选择。实验计划在体外优化导管的输送参数，然后在犬心脏进行体内测试。我们将根据病变大小（宽度、深度和体积）、病变形态、对心内膜和心外膜表面的保护以及愈合病变的促心律失常电位来评估导管的性能。基于导管的成功开发，二期研究将提出开发更精细的原型，增强映射能力和改进的可操作性。该装置随后将在家族性室性心动过速犬模型中进行测试。拟议的商业应用：该研究专门针对开发一种用于治疗室性心动过速（VT）和室性颤动（VF）的改进激光导管。心律失常包括室性心动过速（VT）和室性颤动（VF）在美国每年造成40万例猝死。与其他治疗方法不同，我们的导管有可能为患有VT的患者提供一种治疗手段，因此可能成为此类患者的治疗选择。

Ventricular Tachycardia (VT) is an arrhythmia characterized by an abnormally high rate of ventricular contraction. During VT the ventricles do not fill with sufficient amounts of blood prior to each contraction, often resulting in dizziness, loss of consciousness or sudden cardiac arrest. Catheter ablation has been shown to be an effective means for curing many arrhythmias, but current approaches are not able to coagulate tissue in the midmyocardium or subepicardial regions where foci responsible for VT often originate. In this phase I study we propose to develop and test a novel cooled-tip laser ablation catheter for coagulation of myocardium responsible for the initiation of VT. The novel design includes a proprietary fiber optic delivery system enclosed in a cooled tip that will allow diffusion of thermal energy into deeper layers of the myocardium while preventing damage to the endocardial surface. Additional features will allow real- time monitoring of the electrical activity at the arrhythmogenic site during treatment with the laser. Finally, an inexpensive low-powered diode laser used as the source should make the treatment a more practical clinical option. Experiments are planned to allow optimization of the catheter's delivery parameters in vitro followed by in vivo testing in canine hearts. We will assess the performance of the catheter in terms of lesion size (width, depth, and volume), lesion morphology, protection of the endocardial and epicardial surfaces, and proarrhythmic potential of healed lesions. Based on successful development of the catheter, phase II studies will be proposed to develop a more refined prototype with enhanced mapping capabilities and improved maneuverability. The device will subsequently be tested in a canine model of familial VT. PROPOSED COMMERCIAL APPLICATIONS: This research is specifically targeted towards the development of an improved laser-based catheter for treatment of VT. Cardiac arrhythmias including ventricular tachycardia (VT) and ventricular fibrillation (VF) are responsible for 400,000 cases of sudden death in the U.S. each year. Unlike other therapies, our catheter has potential for providing a curative means for patients who suffer from VT, and therefore could become the treatment of choice in such patients.