Severe mitral regurgitation causes remodeling through enlargement of the left atrium. The enlargement of the atrium is associated with increased risk for atrial fibrillation, ischemic stroke and poorer prognosis. A reversal of the enlargement, known as left atrium reverse remodeling, is observed after the use of Angiotensin Converting Enzyme inhibitors, Angiotensin II Receptor Blockers and cathether ablation in patients with atrial fibrillation. Performing mitral valve repair (MVR) also reverses some of the enlargement through reverse remodeling. A reduction in left atrial volume after MVR is directly related to left atrium reverse remodeling. The research is expected to demonstrate the relationship between left atrial volume reduction and functional improvement of patients with mitral regurgitation in terms of New York Heart Association (NYHA) heart failure classification, residual mitral regurgitation after MVR and Left Ventricular Ejection Fraction (LVEF).