OPTIMIZING ELECTROMECHANICAL RESYNCHRONIZATION (CRT)

优化机电再同步 (CRT)

• 批准号: 6951262
• 负责人: HENERY HALPERIN
• 金额: $ 31.27万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-15 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6951262
• 关键词: cardiovascular disorder therapy; disease /disorder model; dogs; electronic pacemaker; heart block; heart conduction system; heart contraction; heart disorder; heart electrical activity; heart failure; heart imaging /visualization /scanning; hemodynamics; hypertension; magnetic resonance imaging; mathematical model; mechanical stress; medical outreach /case finding; model design /development; nonhuman therapy evaluation; noninvasive diagnosis; pathologic process; prognosis; therapy design /development

Contractile dyssynchrony diminishes systolic function and is a major independent risk factor for worsening heart failure. Cardiac resynchronization therapy (CRT) is a new treatment that involves electrical pre-excitation of the ventricles to recoordinate contraction. Clear identification of patients with ventricular and electrical dyssynchrony is central to targeting patients who are most likely to benefit from CRT. In current practice, widening of the QRS duration is primarily used to identify patients with dyssynchrony who would be candidates for CRT. While non-invasive and convenient, QRS duration and even direct measures of intraventricular electrical delay are only weakly correlated with acute CRT response, and have had little to no predictive value for chronic CRT efficacy. In light of the complexity and health care cost to implement CRT, a noninvasive method to predict responders is highly desirable. We hypothesize that direct image based measurements of mechanical dyssynchrony using magnetic resonance imaging (MRI), regional strain analysis and complete electrical mapping data will allow for the study of the complex relationship between electrical conduction delay and mechanical activation and improve the selection process for CRT candidates. In this project, we use a unique 4D electromechanical imaging and mapping system to address several unanswered and untested mechanistic and practical questions in CRT therapy. In Aim 1 of this project we will test how patho-physiological properties of the failing heart, such as chamber remodeling, cardio-depression, right-heart/septal loading, and myocardial conduction velocity, influence the relationship between conduction delay and mechanical dyssynchrony. In Aim 2 we seek to understand how we can optimize CRT efficacy by factors such as site selection and field versus point stimulation. In Aim 3 we will develop a multivariate prognostic model to identify the extent of mechanical dyssynchrony and responsiveness to resynchronization. This will be derived from magnetic resonance data but focusing on measures that can be derived using other non-invasive methods (echo-Doppler) as well. These studies should provide important elucidation of the mechanisms by which electrical conduction delay alters mechanical dyssynchrony, facilitate the design of optimal pacing algorithms and treatment delivery, and enhance the accuracy of identifying likely responders to CRT therapy.

收缩异构性降低了收缩功能，是心力衰竭恶化的主要独立危险因素。心脏重新同步治疗（CRT）是一种新疗法，涉及对心室的电气预启动以重新配置收缩。清楚地鉴定患有心室和电性障碍的患者对于靶向最有可能受益于CRT的患者至关重要。在目前的实践中，QRS持续时间的延长主要用于识别患有CRT候选者的异同步患者。虽然无创和方便，但QRS持续时间，甚至直接的脑室静电延迟度量仅与急性CRT响应无关 慢性CRT功效的预测价值。鉴于实施CRT的复杂性和医疗保健成本，非常需要预测响应者的无创方法。我们假设使用磁共振成像（MRI），区域应变分析和完整的电气映射数据基于基于图像的直接测量，将允许研究电导传导延迟与机械激活之间的复杂关系，并改善CRT候选者的选择过程。在这个项目中，我们使用独特的4D机电成像和映射系统来解决CRT疗法中几种未经检验和未经测试的机械和实用问题。在该项目的目标1中，我们将测试失败心脏的病理生理学特性，例如腔室重塑，心脏抑郁，右心脏/中间载荷和心肌传导速度，会影响传导延迟与机械性不足的关系之间的关系。在AIM 2中，我们试图了解如何通过诸如现场选择和现场刺激之类的因素来优化CRT疗效。在AIM 3中，我们将开发一个多元预后模型，以确定机械性不合理的范围和对重新同步的响应的程度。这将是 源自磁共振数据，但还专注于可以使用其他非侵入性方法（Echo-Doppler）得出的度量。这些研究应提供重要的阐明，通过这种机制，电导传导延迟改变了机械性异性障碍，促进了最佳起搏算法和治疗递送的设计，并提高了识别可能响应者对CRT治疗的准确性。