The most commonly performed surgical procedures are mitral valve repair and mitral valve replacement. The former is indicated in patients with mild valve damage, no calcification of the leaflets, an enlarged annulus but no severe thickening of the subvalvular tendon cords, low operative mortality, good postoperative improvement in ejection fraction and no lifelong anticoagulation, accounting for 70% of all patients suitable for surgery. The latter is indicated in those with severe valve damage and has an operative mortality rate of approximately 5%.