Creatine kinase typically rises within how many hours after an acute myocardial infarction?

Creatine kinase typically rises within how many hours after an acute myocardial infarction?

• A. 1-2 hours
• B. 4-6 hours
• C. 12-24 hours
• D. 48-72 hours

Answer: (B)

Creatine kinase rises in the blood as heart muscle cells are damaged, releasing the CK-MB isoenzyme into circulation. The earliest detectable rise occurs about four to six hours after an acute myocardial infarction, then it peaks around 24 hours and typically returns to baseline within 48 to 72 hours. So the four-to-six-hour window is the best match for when the rise first appears. Options that are earlier (like 1–2 hours) or later in the course (12–24 or 48–72 hours) don’t reflect the initial rise.

Creatine kinase rises in the blood as heart muscle cells are damaged, releasing the CK-MB isoenzyme into circulation. The earliest detectable rise occurs about four to six hours after an acute myocardial infarction, then it peaks around 24 hours and typically returns to baseline within 48 to 72 hours. So the four-to-six-hour window is the best match for when the rise first appears. Options that are earlier (like 1–2 hours) or later in the course (12–24 or 48–72 hours) don’t reflect the initial rise.