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38 Cards in this Set
- Front
- Back
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Diagnostic tools for MIs:
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Clinical findings
ECG findings cardiac markers |
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Factors that affect cardiac marker measurements:
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- cell release (altered in some disorders like membrane permability or pancreatitis)
- plasma clearance (renal failure increases and prolongs lvls) - age/sex/race (CK higher in males) - methodology (reference ranges according to assay) |
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The ideal cardiac marker should have:
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specificity, rapidly released, wide diagnostic window, precise, cheap, reproducable, provide prognostic information (based upon quantatative level)
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Gold standard for MI detection:
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Troponin
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What is troponin?
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protein that regulates muscle contraction: has T I C subunits
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cardiac specific isoforms of troponin:
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T and I (TI!)
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sensitivity of troponin from 10-120 hours after MI
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100%
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What is a better cTn marker:
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cTnI is more cardio specific and are not elevated in renal failure
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Troponin elevated in:
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AARMMS:
acute PE/acute Pericarditis Renal failure MI/Myocarditis Sepsis./Shock/Severe HF |
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Positive value for cTnI: .
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1-.4 minor MI, definitely >0.4 ng/mL
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CK mainly located in:
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Sk muscle, brain, heart muscle
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Three isoforms of CK:
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1: BB
2: MB 3: MM |
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In what patients is Ck-MB not be diagnostically useful?
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neonates because it is found in large amounts in their serum
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Myoglobin diagnostic window and peak?
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2 hrs, peaks at 6-9 hrs (69!)
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PPV and NPV for myoglobin?
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low PPV, high NPV
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what is IMA?
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ischemia modified albumin; in MI, the ability of cobalt to bind to albumin decreases
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Benefit of ACB?
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albumin cobal binding test can turn positive in less than 1- mins;
used to RULE OUT acute coronary syndrome when troponin and ECG are neg. |
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downfall of ACB?
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low specificity and must be used in conjunction with troponin and ECG testing
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Troponin can stay elevated for how mant days?
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up to 9 for cTnI or 3 weeks for cTnT
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Order of rise in serum markers post MI
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Myoglobin
Troponin CK-MB |
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CK-MB peaks at?
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24 hrs
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CK-MB starts to rise when?
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after Troponin around 4-6 hrs
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troponin peaks when?
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at 3 days, lasts for more than a week
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What might having troponin as part of a cardiac panel help distinguish?
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AMIs that are a day old from one that is several days old
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CK-MB returns to normal when?
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after 48 hrs; if it persists another AMI has occured
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normal CK-MB but slightly elevated troponin
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minor myocardial damage; this is because troponin is much more sensitive than CK-MB
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How can one determine successful vs unsuccessful reperfusion?
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use CK-MB; a earlier and higher peak at 10 hrs indicates sucess
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increased risk for AMI or cardiac death is correlated with what?
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increased cTnT or cTnI levels
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When should serum markers be obtained?
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4-6 hr intervals after onset of pain
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only way AMI can be excluded?
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troponin determinations 8-12 hrs after onset or CK-MB performed 12-24 hrs after onset.
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When are CK-MB and troponin elevated not in an AMI?
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post heart surgery
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Production of what is stimulated by change in LV stretch and volume overload?
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BNP is expressed, wither proBNP or active BNP hormone
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BNP assays used for what?
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distinguish dyspnea due to heart failure vs non cardiac causes
(CHF or not) |
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BNP 50
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CHF not likely (<100)
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BNP 356
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intermediate likelihood of CHF (100-400)
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BNP 569
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CHF very likely (>400)
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BNP levels correlate with what?
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increase in BNP means decrease in LVEF
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BNP used as predictor for what?
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re-admission or death in CHF
recurrence or death in MI |
