Cardiac Magnetic Resonance Imaging After Cardiac Resynchronization Therapy

项目摘要 本研究的主要目的是应用心脏磁共振成像(MRI)技术，对人工心脏植入术后的情况进行研究。 心脏再同步化治疗(CRT)为心力衰竭提供非常详细和高质量的数据 CRT后左室起搏部位特征对左心室结构和功能的影响我们相信 这项工作将提供对CRT响应和无响应的机制以及改进方法的深入了解 CRT实施。心力衰竭的重要性通过以下统计数据来表征：至少500万 在美国，有250万人患有心力衰竭，250万人需要住院治疗，超过50万人患有心力衰竭 每年都被诊断出心力衰竭。因此，这项研究与国家统计局的使命高度一致 心肺和血液研究所，以增进心脏病患者或有心脏病风险的个人的健康 这样他们就能活得更长、更有成就感。CRT涉及植入先进的起搏器/除颤器 连接在心脏上的三根电线，旨在使泵血不均匀的心脏更同步地收缩 而且是有效的。虽然CRT对许多患者非常有益，但无反应率通常为35%-50% 当植入物没有通过成像引导时，通常是因为起搏导线的位置不佳 关于疤痕和机械激活。在K23颁奖典礼上，PI展示了MRI的特征 晚期Gd强化的瘢痕和致密的劳损(置换编码与刺激 ECHES)法可用于确定最佳起搏部位，但可直接用MRI评价起搏效果 CRT后左室起搏部位的重塑直到最近才有可能，当时新一代的 CRT除颤器于2016年2月获准在核磁共振环境中有条件地使用。一种后CRT 心脏MRI提供的数据非常有价值，因为它可以提供非常详细和可重复性的数据 使用针对应变、体积、壁厚、同步性和 刀疤。在这项研究中，CRT后的MRI表现将与CRT前的MRI表现相比较，以显示LV 与机械激活和瘢痕相关的起搏电极位置改变CRT后左室重构并提供 关于LV导联位置和心脏疤痕之间的最佳空间关系的其他见解。磁共振成像 结果将与超声心动图结果进行比较，这一发现有望证明这些 为了CRT患者的利益，各种成像方式可以结合使用。我们将招募40名CRT患者，他们将 有心脏核磁共振、超声心动图、心肺运动试验、症状评估和实验室检查 CRT治疗前和治疗后6个月的检查。该项目预计将在现场产生很高的影响，并导致 CRT实施方面的重要改进。这项工作也将促进PI的发展 独立性，为MRI引导的CRT临床试验后续工作提供重要数据 基于起搏电极放置的CRT术后左室重构计算模型的建立。 1

Project Summary The main objective of this research is to use cardiac magnetic resonance imaging (MRI) after implantation of cardiac resynchronization therapy (CRT) for heart failure to provide very detailed and high-quality data regarding the impact of left ventricular (LV) pacing site characteristics on LV structure and function after CRT. We believe this work will provide insights into mechanisms of CRT response and nonresponse, as well as ways to improve CRT implementation. The importance of heart failure is characterized by the following statistics: at least 5 million people in the United States have heart failure, 2.5 million require hospitalization, and more than 500,000 are diagnosed with heart failure each year. As a result, this research is highly aligned with the mission of the National Heart, Lung, and Blood Institute to enhance the health of individuals with heart disease or at risk for heart disease so they can live longer and more fulfilling lives. CRT involves implantation of an advanced pacemaker/defibrillator attached to three wires in the heart designed to make unevenly pumping hearts contract more synchronously and effectively. Although CRT is very beneficial for many patients, nonresponder rates are typically 35-50% when implants are not guided by imaging, often because of suboptimal positioning of the pacing wires with respect to scar and mechanical activation. During the K23 award, the PI demonstrated how MRI characterization of scar with late gadolinium enhancement and strain with the DENSE (Displacement Encoding with Stimulated Echoes) method before could be used to identify optimal pacing sites, but direct MRI evaluation of the effect of LV pacing sites on LV remodeling after CRT had not been possible until just recently when a new generation of CRT defibrillators was approved for conditional use in the MRI environment in February 2016. A post-CRT cardiac MRI provides is quite valuable because it can provide highly detailed and reproducible data regarding LV structure and function using optimized pulse sequences for strain, volumes, wall thickness, synchrony, and scar. In this study, post-CRT MRI findings will be compared with pre-CRT MRI findings to show how the LV pacing lead location relative to mechanical activation and scar alters LV remodeling after CRT and provide additional insights regarding the optimal spatial relationship between LV lead position and scar in the heart. MRI results will be compared with echocardiography results, and the findings promise to demonstrate how these imaging modalities can be used together for the benefit of CRT patients. We will enroll 40 CRT patients who will have cardiac MRI, echocardiography, cardiopulmonary exercise testing, symptom assessment, and laboratory testing before and 6 months after CRT. The project is expected to have a high impact on the field and lead to important improvements in CRT implementation. This work will also facilitate the PI's progression to independence by providing important data for subsequent work on an MRI-guided clinical trial for CRT and the development of computational models for LV remodeling after CRT based on LV pacing lead placement. 1