Which CK isoenzyme indicates acute myocardial damage?

Which CK isoenzyme indicates acute myocardial damage?

• A. CK-MM
• B. CK-MB
• C. CK-BB
• D. None

Answer: (B)

CK-MB is the heart-specific isoenzyme. When heart muscle is damaged, CK-MB is released into the bloodstream, while CK-MM comes mainly from skeletal muscle and CK-BB from brain. Because CK-MB rises soon after a myocardial injury (about 4–6 hours), peaks around 24 hours, and returns to baseline in a couple of days, it serves as a marker of acute myocardial damage. Today troponin is more specific, but CK-MB was the classic indicator of myocardial injury and is still used in some contexts for detecting reinfarction or when troponin results are equivocal.

CK-MB is the heart-specific isoenzyme. When heart muscle is damaged, CK-MB is released into the bloodstream, while CK-MM comes mainly from skeletal muscle and CK-BB from brain. Because CK-MB rises soon after a myocardial injury (about 4–6 hours), peaks around 24 hours, and returns to baseline in a couple of days, it serves as a marker of acute myocardial damage. Today troponin is more specific, but CK-MB was the classic indicator of myocardial injury and is still used in some contexts for detecting reinfarction or when troponin results are equivocal.