Tuesday, 7 January 2014

Cardiac enzymes Markers

1) CKMB: The MB isoenzyme of creatine phosphokinase is more specific to AMI than CK. AMI
produces a CKMB elevation that peaks approximately 20 h after the onset of coronary occlusion. A
CKMB2: CKMB1 ratio of>1.5 is highly sensitive for the diagnosis of AMI, particularly 4 to 6 h after the onset of coronary occlusion. The MB-CK fraction appears in 4 hours after onset of infarction and peaks at about 24hrs with a duration of 72 hours.
CK MB: 4h - 24h - 72h
2) Cardiac-specific troponin T (cTnT) and cardiac-specific troponin I (cTnI) Since cTnT and cTnI are not normally detectable in the blood of healthy individuals but may increase afterAMI to levels over 20 times higher than the cutoff value. the measurement of cTnT or cTnI is of considerable diagnostic usefulness, and they are now the preferred biochemical markers for MI. Levels of cTnI may remain elevated for 7 to 10 days after AMI, and cTnT levels may remain elevated for up to 10 to 14 days. Thus, measurement of cTnT or cTnI has replaced measurement of lactate dehydrogenase (LDH) and its isoenzymes in patients with
suspected MI who come to medical attention more than 24 to 48 h after the onset of symptoms.
3) LDH on the other hand appears 12 hours after the infarct and peaks 2 days later to last 14 days. LDH has been largely replaced with the more specific cardiac troponin for patients with suspected AMI presenting after the initial 48 hours have passed. LDH: 12h - 48h - 14 days
4) CK: Creatine phosphkinase has been replaced by CKMB due to lack of specificity of CK in AMI.

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