Blood serum CK-MB and cTnI were significantly lower in the loading-dose group than in the conventional-dose group at 24 and 72h post-PCI [ CK-MB : 26.903.22 vs. 32.962.65 IU/L , P = 0.024 ; 10.794.65 vs. 15.185.39 IU/L , P = 0.021 .