Electrophysiologic effects of late PCI (OAT-EP)

描述（由申请人提供）： 现在有明确的证据表明，早期冠状动脉再灌注使用溶栓剂或直接血管成形术的结果在长期死亡率下降的患者谁目前与急性心肌梗死（AMI）。 早期再灌注（AMI发作后< 6小时）的益处机制最初归因于心肌挽救和由此产生的左心室功能保护。 然而，现在很明显，与溶栓治疗相关的生存益处并不总是与左心室射血分数（LVEF）的重大改善相关。 这些观察结果导致了“晚期开放动脉假说”的形成，该假说认为AMI后晚期再灌注可能改善临床结局。 观察性临床研究表明，溶栓后梗死相关动脉（伊拉）的晚期通畅与生存获益相关，且与LVEF无关，因此不能仅通过挽救心肌来解释。 然而，由于先前的前瞻性研究评价了AMI后闭塞IRA的晚期经皮腔内冠状动脉成形术（PTCA），产生了相互矛盾的结果，因此目前缺乏晚期开放动脉假说的可靠证据。 这些考虑导致了闭塞动脉试验（OAT）的组织，这是一项由NHLBI资助的3，200例患者的国际随机试验，旨在验证以下假设：高危患者AMI后3-28天采用PTCA和支架植入术（PCI）对闭塞伊拉进行机械再灌注将降低死亡率、复发性MI和因IV级充血性心力衰竭住院治疗的复合终点。 电稳定性的增强是解释开放性伊拉与独立于心肌挽救的预后改善相关性的主要机制之一。本OAT-EP辅助研究应用将描述闭塞IRA的晚期PCI对最重要和临床相关的恶性室性心律失常易感性无创标志物的影响：心率变异性、T波变异性和信号平均心电图。 将在基线、MI后30天和1年时对300例患者进行这些分析，以分别描述晚期PCI对自主神经系统、心室复极和心室传导异常的影响。

DESCRIPTION (provided by applicant): There is now unequivocal evidence that early coronary reperfusion using either thrombolytics or primary angioplasty results in a long-term mortality reduction among patients who present with acute myocardial infarction (AMI). The mechanism of the benefit of early reperfusion (< 6 hours after AMI onset) was initially attributed to myocardial salvage and the resultant preservation of left ventricular function. However, it is now evident that the survival benefit associated with thrombolytic therapy is not consistently associated with a major improvement in left ventricular ejection fraction (LVEF). These observations led to the formulation of the "late open artery hypothesis", which posits that clinical outcomes can potentially be improved by late reperfusion after AMI. Observational clinical studies have suggested that late patency of the infarct-related artery (IRA) after thrombolysis is associated with a survival benefit that is independent of LVEF and therefore cannot be solely explained by salvage of myocardium. Definitive proof of the late open artery hypothesis is currently lacking, however, because previous prospective studies that have evaluated late percutaneous transluminal coronary angioplasty (PTCA) of occluded IRAs after AMI have produced conflicting results. These considerations led to the organization of the Occluded Artery Trial (OAT), an international, NHLBI-funded randomized trial of 3,200 patients that is testing the hypothesis that mechanical reperfusion of an occluded IRA with PTCA and stenting (PCI) 3-28 days after AMI in high risk patients will reduce a composite endpoint of mortality, recurrent MI, and hospitalization for class IV congestive heart failure. Enhancement of electrical stability is one of the major mechanisms that have been proposed to explain the association of an open IRA with an improved prognosis independent of myocardial salvage. The present OAT-EP ancillary study application will characterize the effects of late PCI of occluded IRAs on the most prognostically important and clinically relevant noninvasive markers of vulnerability to malignant ventricular arrhythmias: heart rate variability, T wave variability, and signal-averaged electrocardiography. These analyses will be performed in 300 patients at baseline, 30 days and one year following MI in order to delineate the effects of late PCI on the autonomic nervous system, ventricular repolarization, and ventricular conduction abnormalities, respectively.