Assessment of Left Ventricle Function Using Color M-Mode Echocardiography

Purdue University, West Lafayette IN

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Abstract

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).