Final answer:
The timeline for CK-MB levels post MI starts with an increase a few hours after the event, peaking around 24 hours, and normalizing in about 48-72 hours. Total CPK levels stay elevated longer post MI, and additional attacks can increase these levels significantly. LDH₁ peaks are maintained for 6 days, and transaminase levels peak within 4 to 5 days post MI.
Step-by-step explanation:
The timeline of elevated levels of creatine kinase MB (CK-MB) post-myocardial infarction (MI) relates to its role as a biomarker in the diagnosis of heart attacks. Usually, CK-MB levels rise within a few hours after the onset of MI, peak at about 24 hours, and return to normal within about 48-72 hours. In comparison, total CPK levels can remain high for 1-2 days post MI, and if a subsequent attack occurs within a short timeframe, the concentration may increase up to 100 times and significantly more with additional attacks. Further, the H4 or LDH₁ isoenzyme form of lactate dehydrogenase sees peak levels in plasma maintained for 6 days after an MI. It's also important to note that transaminases such as aspartyl transaminase (AST or SGOT) peak 4 to 5 days following an attack.