The patient was admitted to the hospital with repeated heart fatigue, shortness of breath for 1+ years, and aggravation for 3+ months. Severe aortic regurgitation, mild mitral regurgitation, and infective endocarditis were diagnosed by preoperative TTE. The patient was scheduled for aortic valve replacement. After anesthesia, TEE confirmed the preoperative ultrasound diagnosis again, and the surgeon performed aortic valve replacement under cardiopulmonary bypass. After cardiopulmonary bypass weaning, TEE found a new regurgitation bundle in the anterior mitral valve leaflet, and the vena contracta was 2 mm. The following reasons were considered:1. The possibility of missed diagnosis by preoperative ultrasonography and intraoperative TEE; 2. Suspected iatrogenic mitral valve injury; 3. The mitral valve was not detected during the operation, and it could not be ruled out that hemodynamic instability aggravates valve damage. The surgeon then performed the mitral valve leaflet repair. Postoperative TEE showed no anterior leaflet regurgitation in the mitral valve,and no paravalvular leakage of the aortic valve. The patient was discharged 12 days after the operation.