Defibrillation mechanisms during ischemic arrhythmias

缺血性心律失常期间的除颤机制

• 批准号: 7121203
• 负责人: GREGORY P WALCOTT
• 金额: $ 18.08万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7121203
• 关键词: arrhythmia; electric countershock heart resuscitation; myocardial ischemia /hypoxia; nonhuman therapy evaluation; pathologic process; sudden cardiac death; swine

Sudden cardiac death is a major cause of mortality in the United States. In an effort to attach this problem, the concept of a Chain of Survival has been presented as a way to characterized the tasks necessary for successful resuscitation. It is clear that early defibrillation is central to improved survival rates following out-of-hospital cardiac arrest. 1) successful defibrillation of the arrhythmia of the arrhythmia, 2) recurrence if arrhythmias following defibrillation, and 3) poor cardiac function following defibrillation This project will address the first two problems. Very little is known about defibrillation efficacy of spontaneous arrhythmias in the presence of acute ischemia. A much larger shock is needed to halt ventricular fibrillation that occurs spontaneously in the presence of acute is ischemia than to halt electrically induced ventricular fibrillation in the non-ischemic heart. We will study the activation patter following successful and failed defibrillation shocks with the heart in four conditions designed to model different aspects of ischemic ventricular fibrillation shocks the heart in four conditions designed to model different aspects of ischemic ventricular fibrillation: (1) acute regional ischemia causing spontaneous ventricular fibrillation, (2) acute regional ischemia followed by electrically induced ventricular fibrillation, (3) acute regional ischemia causing spontaneous ventricular fibrillation which in turn causes prolonged global ischemia, and (4) acute regional ischemia causing spontaneous ventricular fibrillation in the setting of prolonged global ischemia, and (4) acute regional ischemia causing spontaneous ventricular fibrillation in the setting of an old myocardial infarction. We will test the hypothesis that, in the setting of an ischemically induced spontaneous arrhythmia, a defibrillation shock must do three things: (1) stop all fibrillation wavefronts, (2) not restart fibrillation, and (3) stop the trigger of the original arrhythmia. We will test the hypothesis that a major determinant of whether or not a spontaneous arrhythmia, a defibrillation shock must do three things: (1) stop all fibrillation wavefronts, (2)m not restart fibrillation and (3) stop the trigger of the original. We will test the hypothesis that a major determinant f whether or not a spontaneous arrhythmia caused by acute ischemia can be easily defibrillated depends upon the mechanism of initiation of the arrhythmia and duration of the arrhythmia. We will also test the hypothesis that arrhythmias that occur following the initial fibrillation episode are initiated by focal rather than reentrant mechanisms and will be harder to defibrillate than the initial arrhythmia. To test these hypothesis, we will induce acute ischemia by creating a thrombus in a coronary artery and use electrical mapping techniques to map the initiation of ventricular arrhythmias, and the first few post-shock activations following delivery of a defibrillation shock. By developing an understanding of how a defibrillation shock succeeds or fails under these conditions, we will be in a better position to develop new defibrillation techniques that increase survival rates of patients suffering an episode of sudden cardiac death.

心脏猝死是美国死亡率的主要原因。为了解决这个问题，已经提出了一系列生存链的概念，以表征成功复苏所必需的任务。显然，早期除颤对于院外心脏骤停后的生存率提高至关重要。 1）心律不齐的心律不齐的成功除颤，2）复发如果除颤后心律不齐，以及3）除颤后的心脏功能较差，则该项目将解决前两个问题。关于在存在急性缺血的情况下自发性心律不齐的除颤功效知之甚少。在急性存在下自发发生的心室纤颤需要比停止非缺血性心脏的电诱导的心室纤维化，需要更大的冲击。我们将在四个条件下成功地研究成功和失败的除颤冲击后的激活模式，旨在模拟缺血性心室纤维化的不同方面，可在四个条件下进行心脏震动，旨在模拟缺血性心室纤维化的不同方面：（1）急性局部缺血，导致自发性脑纤维化局部触发（2）抗原式静脉曲张，（2）抗脑膜外，（2）抗脑膜异常（2） （3）急性区域缺血引起自发的心室纤维化，反过来导致全球缺血延长，（4）（4）急性区域缺血在延长的全球缺血延长的环境中引起自发性心室纤维化，以及（4）（4）急性缺血性缺血的质量，从而导致自发性纤维质量，从而构成了不元素。我们将检验以下假设：在不变引起的自发性心律失常的情况下，除颤冲击必须做三件事：（1）停止所有颤动的波前，（2）不重新启动颤动，（3）（3）停止原始心律失常的触发器。我们将检验以下假设：除去颤声的主要决定因素是否是自发性心律不齐，必须做三件事：（1）停止所有纤颤波前，（2）M不重新启动纤颤，（3）（3）停止原始触发器。我们将检验以下假设：主要决定因素F是否可以轻松地除原启发，这是否取决于心律不齐和心律不齐的持续时间的机制，这是否很容易被急性缺血引起的自发性心律不齐。我们还将检验以下假设：初始颤动发作后发生的心律不齐是由局灶性而不是再入侵机制引发的，并且比初始心律不齐更难除颤。为了检验这些假设，我们将通过在冠状动脉中创建血栓并使用电气映射技术来绘制心室心律不齐的启动，以及在传递除颤冲击后的前几个后激活。通过对这些条件下的除颤冲击如何成功或失败的理解，我们将有更好的位置开发出新的除颤技术，从而增加患有心脏突然死亡的患者的存活率。