Question | Answer |
Myoglobin, creatine kinase (CK) and lactate dehydrogenase (LD), AST
=Markers of cardiac injury | Damage to the myocardium results in the release of these proteins into the circulation! |
History of chest pain (clinical symptoms)
Abnormal electrocardiogram (ECG)
Rise and fall of cardiac markers in serum | Diagnosis of MI |
Necrosis (death) of an area of the heart muscle produces a Q wave on ECG | |
STEMI (ST elevation MI): severe! Coronary artery completely blocked by clot. Traditional AMI!
Cardiac necrosis, DEATH
NSTEMI (non-ST elevation MI): artery only partially blocked, less severe, tracings also seen in unstable angina | |
Biomarkers released into circulation from damaged myocytes:
AST , LD and its isoenzymes
Then CK and one of its fractions CK-MB | |
CK-MB: in AMI
rises w/in 4-6h, peaks 12-24h, normal 2-3 days | |
Cardiac Proteins | Myoglobin
Cardiac troponins
troponin T (cTnT)
troponin I (cTnI)
Cardiac myosin light chains
CK isoforms |
Myoglobin:
Rises: w/in 2-4h, Peaks: 6-12h,
Normal : 24-36h
nonspec marker | -Known as an EARLY marker!
If normal after 8h, patient did NOT have an MI
-used to RULE-OUT MI
(↑helps to rule-in MI) |
cTnI/cTnT:
Rises: w/in 4-6h,
Peaks: 24h,
Normal : 3-7d (up to 14d) | Used to RULE-IN AMI
cTnI/T are SPECIFIC
Markers |
Cardiac Troponins
Used in identification of unstable angina
No AMI but persistent small increase helps to rule-in UA | |
BNP stimulates Na+ and water loss through kidneys (to relieve ventricular wall stretch and expanded fluid volume associated with CHF)
Increases renal flow and GFR
Discovered to be a marker for CHF! | |