Introduction: Ischemic mitral regurgitation (IMR) is a frequent complication of left ventricular (LV) pathological remodeling after myocardial infarction (MI), which doubles morbidity and mortality. Longitudinal LV remodeling after an MI is not fully understood, therefore large animal studies are needed. In this study, we developed a chronic swine model with IMR and investigated temporal changes of LV remodeling with transesophageal echo (TEE) and pressure-volume (PV) loops. Methods: Yorkshire swine (n=14) underwent induction of a lateral MI through ethanol injection percutaneously into the left circumflex artery (LCX) distal to the first obtuse marginal branch. The animals were survived for 3 months with monthly follow-up TEE. PV loops were performed at baseline, immediately after MI induction, and 3 months post-MI ( Fig.A ). Results: 12 animals survived the MI procedure and developed IMR (average MR grade was 2.6±1.0). LCX occlusion was confirmed with coronary angiogram at 3 months post-MI. EDV and ESV were significantly increased at 3months compared to baseline (156.5±53.0 vs 63.3±7.2ml, p<0.0001, and 83.2±31.4 vs 25.5±5.1ml, p<0.0001, respectively). EF decreased 39.7±7.2% just after infarction compared to 59.4±4.3% at baseline (p=0.0001) and increased at 1 and 2 months, then decreased again at 3 months (53.6±8.1, 55.9±6.3, and 46.7±7.6%, respectively) ( Fig.B ). In invasive hemodynamics, end-systolic elastance, preload adjusted dP/dt max , and end-diastolic pressure-volume relationship significantly decreased at 3 months indicating both systolic and diastolic dysfunction. Arterial elastance at 3 months was significantly lower than baseline indicating a reduction of afterload due to MR ( Fig.C ). Conclusions: A lateral MI resulted in an acute reduction in EF, followed by development of IMR, chronic LV dilation, and decreased systolic and diastolic function over 3 months. Temporary improvement of EF after MI may indicate reduced afterload due to MR.