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

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 心力衰竭是发病/死亡的主要原因，在美国影响近500万人。 心脏起搏治疗（CRT）对许多此类患者具有巨大的潜在临床受益，但由于难以识别合适的患者和左心室电极导线放置的技术限制，其应用受到限制。 该项目应用一种新的心脏磁共振（CMR）脉冲序列，用于被称为电影DENSE（刺激回波位移编码）的应变，以评价接受CRT的患者。 值得注意的是，电影DENSE在弗吉尼亚大学得到了很大程度的发展，如初步数据所示，即使在左心室扩张和变薄的患者中，也能产生非常高质量的局部应变数据。 在本研究中，我们将检验以下假设：在预测CRT反应方面，CMR结合DENSE评估环周机械不同步和瘢痕成像比超声心动图显著更准确，当左心室电极导线位于显著瘢痕内或附近时，可能导致无反应。 具体目标是：1）使用电影DENSE评估基于CMR的机械不同步评价的临床用途，以准确预测CRT反应（通过标准反应指数测量）; 2）使用CMR瘢痕成像和三维瘢痕图建立左心室电极导线位置与基础心肌基质之间的最佳关系。 为了实现这些目标，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，然后进行临床CRT手术。 然后在CRT后6个月重复这些基线评估，并进行3年长期随访。 数据分析中使用的统计方法包括Fisher精确检验、McNemar检验、逻辑回归和生存分析。 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.