Biventricular Pacing After Cardiopulmonary Bypass

描述（由申请人提供）：双室起搏（BiVP）逆转扩张型心肌病（DCM）的室内传导延迟（IVCD）和左室（LV）日功能。BiVP在不消耗能量的情况下改善左室功能和心脏指数（Cl）。在DCM、IVCD和左室射血分数<35%的患者中进行的MIRACLE试验表明，使用BiVP可改善运动耐量和心功能的主观和客观测量。BiVP使许多人受益，但选择标准尚未完全制定，30%的接受者是“无反应者”，每年的成本超过20亿美元。初步数据表明，BiVP可以使心脏手术后低输出状态的患者受益。我们计划评估BiVP的手术应用，同时评估作用机制和优化。我们将190例术前左室功能不全的心脏手术患者随机分为有节奏组和无节奏组。将优化BiVP并在术后继续使用，直至患者病情稳定。所有患者的BiVP将在三个时间点进行瞬时评估。主要终点是在重症监护病房（ICU）测量的热稀释Cl改善15%。心率、房室延迟、心室起搏部位和W时间对Cl的影响将采用随机数据收集序列进行评估。次要终点包括心律失常发生率、肌力支持、尿量、体重增加、发病率、死亡率和ICU费用。在三组14名心脏移植受者中进行的相关研究将评估BiVP对有或没有肌力支持的DCM或缺血性肌病原位衰竭心脏的机制的影响。主要终点仍然是Cl升高，但每位患者将接受随机序列的数据收集，包括6个左心室起搏点的54点矩阵和14分钟内的9个W计时，同时记录Cl、收缩性、室内和室间同步性以及二尖瓣反流的测量。结果将显示在二维响应面上，以确定最佳的BiVP优化技术。将对Cl升高< 20%的患者进行详细评估，以确定无效的病因。这些研究很重要，因为临床获益的可能性很大。所采用的方法将提供精度、测量宽度和起搏位置范围优于任何其他设置。该方案将提供新的和重要的科学信息，不仅有利于外科患者，也有利于BiVP接受者的一般人群。

DESCRIPTION (provided by applicant): Biventricular pacing (BiVP) reverses intraventricular conduction delay (IVCD) and left ventricular (LV) dys- function in dilated cardiomyopathy (DCM). BiVP improves LV function and cardiac index (Cl) at no energy cost. The MIRACLE trial, in patients with DCM, IVCD and LV ejection fraction <35%, demonstrated improved subjective and objective measures of exercise tolerance and cardiac function with BiVP. BiVP benefits many, but selection criteria are not fully developed, and 30% of recipients are "nonresponders," at a cost of more than $2 billion/year. Preliminary data suggest that BiVP can benefit patients with low output states after cardiac surgery. We plan to assess surgical application of BiVP while assessing mechanisms of action and optimization. We will randomize 190 cardiac surgery patients with LV dysfunction preoperatively to paced and unpaced groups. BiVP will be optimized and continued postoperatively until patients are stable. BiVP will be assessed transiently in all patients at three time points. The primary end point is a 15% improvement in thermal dilution Cl measured in the intensive care unit (ICU). Effects of heart rate, atrioventricular delay, ventricular pacing site, and W timing on Cl will be assessed using a randomized sequence of data collection. Secondary end points include incidence of arrhythmias, inotropic support, urine output, weight gain, morbidity, mortality, and ICU costs. Related studies in three groups of 14 cardiac transplant recipients will assess BiVP effects on mechanics of in situ failing hearts with DCM or ischemic myopathy with or without inotropic support. The primary end point again is an increase in Cl, but each patient will undergo a randomized sequence of data collection for a 54-point matrix of six left ventricular pacing sites and nine W timings over 14 minutes, while measurements of Cl, contractility, intraventricular and interventricular synchrony and mitral regurgitation are recorded. Results will be displayed on two-dimensional response surfaces to define the best techniques for BiVP optimization. Patients with an increase in Cl < 20% will be assessed in detail to determine the etiology of failure to respond. These studies are important because of a high probability of clinical benefit. The methods employed will provide precision, breadth of measurement, and range of pacing sites superior to any other setting. The protocol will provide new and important scientific information that will benefit not only surgical patients but also the general population of BiVP recipients.