Although statin has been used to low cholesterol to prevent and treat coronary artery disease for many years, it has been reported that statin could protect endothelial function and cardiac function in coronary artery bypass graft. However, some results were controversy. Also, there is no clinical data available on statin cardiac protection during surgery in China where rheumatic heart disease is prevalence.Thus, it is necessary to perform a double blind, randomised clinical trial in China to determine whether statin can protect heart injury during heart surgery in China and what's its mechanism.