CARDIAC MAGNETIC RESONANCE, CRT RESPONSE, OPTIMAL LEFT VENTRICULAR PACING SITE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 心力衰竭是发病率/死亡率的主要原因，在美国有近500万人受到影响。心脏再同步治疗(CRT)对其中一些患者有很大的潜在临床益处，但由于难以找到合适的患者和左心室导联放置的技术限制，其应用受到限制。该项目将一种新的心脏磁共振(CMR)脉冲序列应用于CRT患者的评估，该序列被称为Cine Dense(利用刺激回声进行置换编码)。值得注意的是，在弗吉尼亚大学已经在很大程度上开发了Cine Density，正如初步数据所示，即使在左心室扩大和变薄的患者中，也能产生非常高质量的区域应变数据。在这项研究中，我们将验证这样一种假设，即在预测CRT反应方面，CMR对周向机械不同步和疤痕成像的密集评估明显比超声心动图更准确，而无反应可能是当左心室导联位于显著瘢痕或附近时的结果。其具体目的是：1)评估基于CMR的机械不同步评估的临床应用，使用Cine Dense准确预测CRT反应(以标准反应指数衡量)；以及2)使用CMR疤痕成像和三维疤痕图建立左心室导联位置与潜在心肌基质之间的最佳关系。为了达到这些目标，我们正在进行一项前瞻性研究，包括基线临床评估、心脏成像、心肺运动试验和神经激素评估，随后进行临床CRT程序。这些基线评估将在CRT后6个月重复，并进行3年的长期随访。数据分析中使用的统计方法将包括费舍尔精确检验、麦克内马尔检验、Logistic回归和生存分析。我们相信，这项工作的发现将对许多心力衰竭患者具有重大的公共卫生意义。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Heart failure is a major cause of morbidity/mortality and affects nearly 5 million people in the United States. Cardiac resynchronization therapy (CRT) has great potential clinical benefit for a number of these patients, but application is limited by difficulty identifying appropriate patients and technical limitations regarding left ventricular lead placement. This project applies a novel cardiac magnetic resonance (CMR) pulse sequence for strain known as cine DENSE (displacement encoding with stimulated echoes) to the evaluation of patients undergoing CRT. Of note, cine DENSE has been largely developed here at the University of Virginia and, as shown in the preliminary data, yields very high quality regional strain data even in patients with dilated and thinned left ventricles. In this study, we will test the hypothesis that CMR with DENSE assessment of circumferential mechanical dyssynchrony and scar imaging is significantly more accurate than echocardiography in predicting CRT response, with nonresponse the likely result when the left ventricular lead is positioned in or near significant scar. The specific aims are: 1) to assess the clinical use of CMR-based evaluation of mechanical dyssynchrony using cine DENSE for accurate prediction of CRT response, as measured by standard response indices; and 2) to establish the optimal relationship between left ventricular lead position and the underlying myocardial substrate using CMR scar imaging and three-dimensional scar maps. To address these aims, we are performing a prospective study with baseline clinical assessment, cardiac imaging, cardiopulmonary exercise testing, and neurohormonal assessment, followed by the clinical CRT procedure. These baseline assessments will then be repeated 6 months after CRT, with long-term 3-year follow-up. Statistical methods used in the data analysis will include Fisher's exact test, McNemar's test, logistic regression, and survival analysis. We believe the findings of this work will be of major public health importance to many patients with heart failure.