Abstract #1762

Twelve Weeks of Chronic Mitral Regurgitation Alters Myocardial Structure as Measured by Diffusion Tensor MRI

Daniel Bruce Ennis¹, Tom C. Nguyen², Gabriel R. Barnard¹, Aki Itoh², Stefan Skare³, Wolfgang Bothe², Neil B. Ingels², D C. Miller²

¹Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA; ²Department of Cardiothoracic Surgery, Stanford University, Palo Alto, CA, USA; ³Department of Radiology, Stanford University, Palo Alto, CA, USA

Left ventricular (LV) dysfunction in chronic mitral regurgitation (MR) may result, in part, from changes in LV microstructure and diffusion tensor magnetic resonance imaging (DTMRI) is well suited for the evaluation of microstructural organization. The <B>objective</B> of this study was to determine whether twelve-weeks of chronic MR alters the LV myocardial microstructure as measured with DTMRI. Comparisons between LV microstructural measures in normal sheep and chronic MR sheep demonstrate a significant (P<0.000001) increase in the rate of water diffusion (trace) and a decrease in fractional anisotropy (FA). These changes may have a direct impact on ventricular systolic and diastolic function.