Conventional cardiac operations are performed with median sternotomy, which is related to great wound, morbidities, longer duration in hospital and most significantly, cosmetic problems. The investigators invested a new minimally invasive cardiac operation method totally under video-endoscope and peripheral cardiopulmonary bypass. The investigators' hypothesis is that this new minimally method could provide better cosmetic effects to the patients, and also relate to shorter postoperative hospital stay and better recovery.