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.

心源性猝死是美国死亡的主要原因。为了解决这个问题，提出了生存链的概念，作为描述成功复苏所需任务的一种方法。显然，早期除颤对于提高院外心脏骤停后的生存率至关重要。 1) 成功对心律失常进行除颤，2) 除颤后心律失常复发，以及 3) 除颤后心功能不佳 该项目将解决前两个问题。关于急性缺血情况下自发性心律失常的除颤效果知之甚少。与停止非缺血心脏中电诱发的心室颤动相比，需要更大的电击来停止在存在急性缺血的情况下自发发生的心室颤动。我们将研究在旨在模拟缺血性心室颤动不同方面的四种条件下对心脏进行成功和失败的除颤电击后的激活模式在旨在模拟缺血性心室颤动不同方面的四种条件下对心脏进行电击：（1）引起急性局部缺血自发性心室颤动，(2) 急性局部缺血，随后发生电诱发心室颤动，(3) 急性局部缺血引起自发性心室颤动，进而引起自发性心室颤动长期整体缺血，以及（4）在长期整体缺血的情况下引起自发性心室颤动的急性局部缺血，以及（4）在陈旧性心肌梗塞的情况下引起自发性心室颤动的急性局部缺血。我们将检验以下假设：在缺血性自发性心律失常的情况下，除颤电击必须做三件事：（1）停止所有颤动波前，（2）不重新启动颤动，以及（3）停止原始颤动的触发心律失常。我们将检验这样的假设：是否是自发性心律失常的主要决定因素是除颤电击必须做三件事：(1) 停止所有颤动波前，(2) 不重新启动颤动，以及 (3) 停止原始颤动的触发。 。我们将检验以下假设：由急性缺血引起的自发性心律失常是否容易除颤的主要决定因素取决于心律失常的起始机制和心律失常的持续时间。我们还将检验以下假设：初始颤动发作后发生的心律失常是由局灶性而非折返机制引发的，并且比初始心律失常更难除颤。为了检验这些假设，我们将通过在冠状动脉中产生血栓来诱发急性缺血，并使用电测绘技术来绘制室性心律失常的起始图，以及除颤电击后最初的几次电击后激活图。通过了解除颤电击在这些情况下如何成功或失败，我们将能够更好地开发新的除颤技术，提高心源性猝死患者的生存率。