There were divided into two groups: HTK solution group and cold blood cardioplegia group, conducted from 9/2016 to 5/2017 at Cho Ray Hospital. The effect of myocardial protection was evaluated by screening: cardiac enzymes regarding Troponin I and CK-MB that released after aortic unclamping, ventricular fibrillation, and the use of inotropic agents after aortic unclamping.