Assessment of Left Ventricle Function Using Color M-Mode Echocardiography

描述（由申请人提供）：我们假设左室充盈动力学在已知有心功能障碍的患者组中被改变。HF伴EF bb0 0.50， HF伴EF <0.40，左室肥厚)与正常人比较。这些变化表现为初始Vp的降低和从二尖瓣到减速点的距离的减小。充填波的减速与左室内逆压梯度的发生之间的关系建立了控制充填的物理机制。此外，我们假设一个新的参数，早期充盈强度（Vs），结合了初始Vp和减速距离，与传统的舒张功能测量（即Vp， e， e /e或等体积应变率）相比，可以更好地将这些患者组与正常人区分开来。我们的初步工作证明了我们的建议的可行性，我们的初步观察与我们的假设是一致的。我们将通过以下具体目标来探索上述假设：1)自动化CMM分析以客观评估舒张充盈并消除操作人员之间的差异。在我们的初步工作中，我们通过使用半自动算法分析单个心跳完成了这一点。我们现在将这种方法扩展到自动评估来自多个节拍的数据，提高了分析的易用性和准确性。2)通过测量血流传播速度及其时间变化和评估临床获得的CMM超声心动图的室内压力梯度，开发一种基于物理的方法来表征舒张充盈。3)在一项前瞻性研究中评估舒张早期血流传播速度和室内压力梯度，该研究将包括EF保存和EF减少的健康患者和患病患者，使我们能够检验我们关于舒张早期左室充盈正常和异常的物理基础的假设，并与传统的舒张功能测量（即Vp， e′，e /e′，等容应变率）进行比较。

DESCRIPTION (provided by applicant): We hypothesize that LV filling dynamics are altered in patient groups known to have cardiac dysfunction (ie. HF with EF >0.50, HF with EF <0.40, and LV hypertrophy) compared to normals. These alterations are manifested by a reduction of the initial Vp and reduction of the distance from the mitral valve to the point where the deceleration occurs. The relationship between the deceleration of the filling wave and the onset of the adverse pressure gradient within the LV establishes the physical mechanism governing the filling. In addition we hypothesize that a novel parameter, the early filling strength (Vs), that combines the initial Vp and the deceleration distance, better separates these patient groups from normals compared to conventional measures of diastolic function (i.e. VP, e , E/e , or iso-volumetric strain rate). Our preliminary work demonstrates the feasibility of our proposal, and our initial observations are consistent with our hypotheses. We will explore the above hypothesis by pursuing the following specific aims: 1) Automate the CMM analysis to objectively assess diastolic filling and eliminate inter-operator variability. In our preliminary work we have accomplished this by using a semi-automated algorithm analyzing single heartbeats. We will now extend this method to automatically assess data from multiple beats, improving the ease of use and accuracy of the analysis. 2) Develop a physics-based method for characterizing diastolic filling by measuring the velocity of flow propagation and its temporal variations and assessing the intraventricular pressure gradients from clinically obtained CMM echocardiograms. 3) Assess early diastolic flow propagation velocities and intraventricular pressure gradients in a prospective study that will include healthy patients and diseased patients both with preserved and reduced EF, allowing us to test our hypothesis regarding the physical basis for normal and abnormal early diastolic LV filling and compare to conventional measures of diastolic function (i.e. Vp, e', E/e', isovolumetric strain rate). PUBLIC HEALTH RELEVANCE: The goal of this project is to overcome limitations with the accurate estimation of the propagation velocity and delineate the filling mechanics related to Vp. Subsequently, utilize this knowledge to develop a physically consistent, accurate and robust methodology for quantifying the early diastolic filling. A new parameter, the early filling strength (Vs), that combines the initial Vp and the deceleration distance, will be developed and we will show that it better separates patient groups from normals. Success in this effort will allow better insight in the physics of diastolic dysfunction and will re-assert Vp as a reliable metric that will work in concert with other diagnostic parameters.