MAE Seminar

Novel Experimental and Modeling Approaches to Cardiac Assessment and Cardiovascular Devices  

 March 11, 2011

Arash Kheradvar

 It has been shown that the traditional echocardiographic criteria for diagnosis and grading cardiac dysfunction may not be sufficiently reliable, and several measurements are needed to characterize the dysfunction. This is particularly true with respect to diastolic dysfunction. Despite the importance of early diagnosis for diastolic dysfunction, prompt characterization of dysfunction still remains unclear. The method of choice for assessment of the left ventricular function -cardiac catheterization- is invasive and inappropriate for screening purposes. Conventional non-invasive Doppler measurements have low sensitivity, specificity and predictive accuracy which lead us to underestimate the progress of dysfunction. This type of confusion especially arises during the conversion from mild to moderate stages of disease, and hides the progress of the dysfunction due to pseudonormalization. In this seminar, I will describe how experimental mechanics can help us better approach the evaluation of cardiac dysfunction. The presence of vortical flow structures that develop along with transmitral flow during diastole has been demonstrated via different imaging modalities. Thus, physical characteristics of these vortices may provide more reliable measures of diastolic function than existing indexes. Process of formation of a vortex is described by the non-dimensional index of “vortex formation time”. The normal characteristics of the transmitral flow vary in a number of cardiac dysfunctions, and these changes are reflected on the vortex formation process. I will show how vortex formation time as a fluid dynamics parameter can be used as a global index that quantifies diastolic function

In this seminar, I will also briefly review the current research activities of our laboratory, and in particular discuss our recent progress on design and development of novel bioprosthetic and percutaneous heart valves.