Effect of mitral valve replacement on reduction of left atrial size

INTRODUCTION: asymptomatic left atrial enlargement is not uncommon in rheumatic mitral valve disease. We studied the change in size of the left atrium after mitral valve replacement. PATIENTS AND METHODS: between January and December 2005, 116 patients underwent isolated mitral valve replacement. Two groups were identified based on left atrial size: group 1 < 60 mm (n = 79) and group 2 > 60 mm (n = 37). The patients were followed up for 40.4 ± 19.3 months Clinical assessment, preoperative and last postoperative echocardiograms were considered for analysis. RESULTS: the left atrium decreased by 5.84 mm ± 10.5 in group 1 compared to 20.9 mm ± 10.64 in group 2 (p = 0.0001). This correlated with preoperative mitral valve area (p = 0.009), preoperative mitral regurgitation (p = 0.000), and preoperative atrial fibrillation (p = 0.022). Linear regression analysis revealed atrial fibrillation (p = 0.001, b1 = 6.006), a high grade of mitral regurgitation (p = 0.001, b1 = -3.812), and larger size of the left atrium (p = 0.000, b1 = -0.701) predicted a greater reduction of left atrial size during follow-up. Left atrial size decreased by 28 mm in patients with a preoperative left atrium >60 mm (75% sensitivity and 100% specificity). CONCLUSION: the asymptomatic left atrium reduces in size considerably after mitral valve replacement, and the decrease is greater in patients with a left atrium >60 mm in size.