VERY LOW ENERGY CARDIOVERSION FOR ATRIAL FIBRILLATION

极低能量心脏复律治疗心房颤动

• 批准号: 6402796
• 负责人: PATRICK D WOLF
• 金额: $ 26.95万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6402796
• 关键词: atrial fibrillation; biomedical device power system; biomedical equipment development; electronic pacemaker; epicardial mapping; heart electrical activity; implantable defibrillators; medical implant science; sheep

Internal atrial defibrillation is a successful therapy for the treatment of atrial fibrillation(AF). Current internal atrial defibrillators(IAD) use conventional defibrillation technology to deliver high energy shocks with a high likelihood of success. The applied shock strength of 3-10 Joules is above a patient's pain threshold and this limits the broad application of IAD therapy. A technology is proposed that utilizes multiple very low energy (less than .5J) shocks(VLES) with a low probability of first shock success but a high cumulative probability of conversion. A telemetry system will be implanted in an ovine model of AF. The combined animal model and telemetry system will be used as a test bed for VLES atrial cardioversion. The telemetry unit transmits 4 electrograms a distance of 10 meters and delivers continuous and programmed pacing by remote control. This system will be enhanced by adding pressure monitoring and VLES circuitry. It will be used 1) to characterize electrical remodeling and to track changes in infra-atrial pressure induced by the rapid pacing protocol and 2) to measure the energy that corresponds to a 5 percent level of success, and 3) to test three strategies for increasing the VLES probability of success. The three strategies are: 1) pre-VLES overdrive pacing 2) pre-VLES non-linear dynamics based pacing, and 3) use of class III antiarrhythmic drugs with VLES. Epicardial mapping will be used to identify the mechanism of VLES defibrillation and to characterize the effects of the 3 enhancement strategies. The work proposed in this grant will advance the science of remote testing in unanesthetized animals, will characterize the development of electrical modeling and myocardial pathology produced by rapid pacing in sheep, and will test a total of four strategies for very low energy atrial defibrillation. These advances will increase our understanding of the progression of AF and allow a successful therapy for this debilitating disease to be more broadly applied.

心房除颤是治疗心房颤动（AF）的一种成功方法。目前的内部心房除颤器（IAD）使用传统的除颤技术来提供高成功率的高能量冲击。施加的3-10焦耳的冲击强度高于患者的疼痛阈值，这限制了IAD治疗的广泛应用。提出了一种利用多个极低能量(小于。5J)冲击（VLES），第一次冲击成功概率低，但累积转换概率高。将遥测系统植入AF羊模型，将动物模型与遥测系统结合作为VLES心房转复的试验台。遥测单元传输4个10米距离的电图，并通过遥控器提供连续和可编程的起搏。该系统将通过增加压力监测和VLES电路来增强。它将用于1)表征电重构并跟踪由快速起搏方案引起的心房下压变化；2)测量5%成功水平对应的能量；3)测试三种提高VLES成功概率的策略。这三种策略是：1)VLES前的超速起搏；2)VLES前的非线性动态起搏；3)在VLES时使用III类抗心律失常药物。心外膜测图将用于确定VLES除颤的机制，并表征3种增强策略的效果。这项拨款提出的工作将推进在非麻醉动物中进行远程测试的科学，将描述由绵羊快速起搏产生的电建模和心肌病理的发展，并将测试四种极低能量心房除颤策略。这些进展将增加我们对房颤进展的理解，并使这种使人衰弱的疾病的成功治疗得到更广泛的应用。