Changes of myocardial enzymes in acute myocardial infarction.

① Creatine phosphokinase (CK) increased within 6 hours after onset. It reached its peak in 24 hours and returned to normal in 3 ~ 4 days. ② aspartate aminotransferase increased after 6 ~ 12 hours, reached the peak in 24 ~ 48 hours, and decreased to normal after 3 ~ 6 days. ③ Lactate dehydrogenase increased at 8 ~ 10 hour after onset, reached the peak at 2 ~ 3 days, and returned to normal after 1 ~ 2 weeks. ④ CK isoenzyme CK-MB has the best diagnostic specificity. It increased within 4 hours after onset, and/kloc-0 reached its peak in 6-24 hours and returned to normal in 3-4 days. Its elevation can accurately reflect the infarct size, and whether its peak appears in advance is helpful to judge whether thrombolytic therapy is successful or not.