LASER CATHETER FOR ABLATION OF VENTRICULAR TACHYCARDIA

室性心动过速（VT）是一种以心室收缩率异常高为特征的心律失常。 在室性心动过速期间，心室在每次收缩之前没有填充足够量的血液，通常导致头晕、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层或心外膜下区域中的组织，而这些区域通常是导致VT的病灶的起源。在本I期研究中，我们建议开发和测试一种新型的冷头激光消融导管，用于凝固引起VT的心肌。该新颖设计包括封闭在冷却尖端中的专有光纤输送系统，该系统将允许热能扩散到心肌的更深层，同时防止损伤内膜表面。其他功能将允许在激光治疗期间对致瘤部位的电活动进行真实的实时监测。最后，一种廉价的低功率二极管激光器作为光源应该使治疗成为一个更实用的临床选择。计划进行实验，以优化导管的体外输送参数，然后在犬心脏中进行体内测试。我们将评估导管在病变尺寸（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预防潜力方面的性能。在成功开发导管的基础上，将提出第二阶段研究，以开发具有增强的标测能力和改进的可操作性的更精细的原型。随后将在家族性室性心动过速犬模型中对该器械进行测试。拟议的商业应用：本研究专门针对开发用于治疗VT的改进型激光导管。在美国，包括室性心动过速（VT）和室颤（VF）在内的心律失常每年导致40万例猝死。与其他疗法不同，我们的导管有可能为室性心动过速患者提供治疗手段，因此可能成为此类患者的首选治疗方法。

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.