Defibrillation of Ischemic Ventricular Fibrillation

描述(申请人的逐字描述)：心脏性猝死是一种 是美国人死亡的主要原因。为了努力打击这一点 问题，生存链的概念已经被提出作为一种方式 描述成功复苏所必需的任务。早些时候 除颤是提高出院后存活率的核心 心脏骤停。对心脏除颤的疗效知之甚少。 急性缺血时的自发性心律失常。更大的冲击 需要用来阻止自发性的室颤 存在急性缺血而不是停止电诱导的心室 非缺血型心脏的纤颤。我们将研究激活模式 在成功和失败的除颤电击后，心脏有四个 设计用于模拟不同方面的缺血室的条件 纤颤：(1)急性局部缺血引起的自发性心室 纤颤，(2)急性局部缺血，继之电诱导 室颤，(3)急性局部缺血引起自发性 室颤，进而导致长时间的全脑缺血，以及 (4)急性局部缺血引起自发性室颤 陈旧性心肌梗死的背景。我们将测试假设，在 缺血诱发的自发性心律失常的设定，即除颤 电击必须做三件事：(1)停止所有纤颤波前；(2)不 重新启动纤颤，以及(3)停止触发原有心律失常。我们 也将检验这一假设，即一个主要决定因素是否 急性缺血引起的自发性心律失常很容易除颤 取决于心律失常的启动机制和持续时间 心律不齐。为了验证这些假说，我们将使用电子地图技术 来标示室性心律失常的起始点，然后标示前几个 除颤电击后的电击后激活。通过 了解除颤电击是如何成功或失败的 在这些条件下，我们将更好地发展新的 除颤技术有望提高患者的存活率 患有心源性猝死的患者。

DESCRIPTION (the applicant's description verbatim): Sudden Cardiac Death is a major cause of mortality in the United States. In an effort to attack this problem, the concept of a Chain of Survival has been presented as a way to characterize the tasks necessary for a successful resuscitation. Early defibrillation is central to improved survival rates following out of hospital cardiac arrest. 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 ischemia than to halt electrically induced ventricular fibrillation in the non-ischemic heart. We will study the activation patterns following successful and failed defibrillation shocks with 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 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 also test the hypothesis that a major determinant of 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. To test these hypotheses, we will use electrical mapping techniques to map the initiation of ventricular arrhythmias, and then map the first few post-shock activations following delivery of a defibrillation shock. By developing an understanding of how a defibrillation shock succeed or fails under these conditions, we will be in a better position to develop new defibrillation techniques that will hopefully increase survival rates of patients suffering an episode of sudden cardiac death.