A 70-year-old patient who survived about 40 years after left pneumonectomy for tuberculosis visited emergency hospital, because of dyspnea. She received suitable medical therapy for atirial fibrillation and severe mitral regurgitation and hesitated heart surgery because of anxiety for surgical risk. The computed-tomography showed mediastinal shift to left and right lung compensatory expansion. Respiratory function test after treatment of heart failure showed only mild restrictive disorder. And the blood-gas examination in room air was 101 mmHg of Pao2 and 37 mmHg of Paco2. The mitral valve replacement was performed via median sternotomy and using normal cardiopulmonary bypass. And she fully recoverd without any respiratory complications. Mediastinal shift did not obstract the surgical view and establishment of cardiopulmonary bypass in this case. It seemed that the key of surgical successs is the preserved function of healthy residual lung.