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Cardiac Function
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! |