Biventricular Pacing After Cardiopulmonary Bypass

描述(申请人提供)：双室起搏(BIVP)可逆转扩张型心肌病(DCM)患者的室内传导延迟(IVCD)和左心室(LV)功能障碍。BIVP可在不消耗能量的情况下改善左心功能和心脏指数(CI)。在DCM、IVCD和LV射血分数<35%的患者中进行的奇迹试验表明，BIVP改善了运动耐量和心功能的主观和客观指标。BIVP使许多人受益，但选择标准还没有完全制定，30%的受助者是“无回应者”，每年的费用超过20亿美元。初步数据表明，BIVP可以使心脏手术后低输出量状态的患者受益。我们计划评估BIVP的外科应用，同时评估其作用机制和优化。我们将190例心脏手术患者随机分为起搏组和非起搏组。BIVP将在术后得到优化并持续到患者稳定为止。将在三个时间点对所有患者进行一过性BIVP评估。主要终点是在重症监护病房(ICU)测量的热稀释氯改善15%。心率、房室延迟、室性起搏部位和W向起搏时间对CI的影响将使用随机数据收集序列进行评估。次要终点包括心律失常的发生率、肌力支持、尿量、体重增加、发病率、死亡率和ICU费用。三组14名心脏移植受者的相关研究将评估BIVP对患有扩张性心肌病或缺血性肌病的原位衰竭心脏在肌力支持或不支持的情况下的力学效果。主要终点同样是心脏收缩指数的增加，但每个患者都将接受随机序列的数据收集，在14分钟内收集由6个左心室起搏部位和9个W定时组成的54点矩阵，同时记录心脏收缩指数、室内室间同步性和二尖瓣返流。结果将显示在二维响应表面上，以定义BIVP优化的最佳技术。将对CL&lt；20%增加的患者进行详细评估，以确定无反应的原因。这些研究很重要，因为临床受益的可能性很高。所采用的方法将提供优于任何其他设置的精度、测量范围和起搏部位的范围。该方案将提供新的重要科学信息，这些信息不仅将使手术患者受益，而且将使BIVP接受者的普通人群受益。

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.