Mitral Regurgitation Augments Post-Myocardial Infarction Remodeling: Failure of Hypertrophic Compensation Ronen Beeri, Chaim Yosefy, J. Luis Guerrero, Francesca Nesta, Suzan Abedat, Miguel Chaput, Federica del Monte, Mark D. Handschumacher, Robert Stroud, Suzanne Sullivan, Thea Pugatsch, Dan Gilon, Gus J. Vlahakes, Francis G. Spinale, Roger J. Hajjar, Robert A. Levine Mitral regurgitation (MR) doubles mortality after myocardial infarction (MI), but its additive contribution to left ventricular remodeling is debated and has not been addressed in a controlled fashion. In a sheep model with apical MI and a standard moderate MR, we observed excess remodeling as compared with MI without MR, as manifested by increased gross remodeling morphology by 3-dimensional echocardiography, reduced intrinsic contractility at the global and cellular levels, exhaustion of pro-hypertrophic signaling in the cardiomyocytes, and increased extracellular matrix turnover. Hence, MR worsens post-MI remodeling.