cardiac markers Flashcards
- Heme-containing protein that binds oxygen with cardiac and skeletal muscle
- Levels are related to musde mass and activity (raasonable sensitivity but poor specificty)
Clinical Significance:
* Increased in skeletal injuries, muscular dystrophy, and AMI
- released early in cases of AMI, rising in 1-3 hours and peaks in 5-12 hours, and returns to normal in 18-30 hours. However, it is not tissue specific. It is better used as a negative predictor in the first 2-4 hours following chest pain
myoglobin
troponin
- Assessment of early and late AMI
- Onset: 3-4 hours; Elevated up to 1-14 hours
- Sensitive marker for the diagnosis of unstable angina.
- But it is also elevated in renal diseases and skeletal diseases.
- It is also detected in fetal skeletal muscle
troponin T
troponin
- only found in the myocardium
- greater cardiac specificity than Troponin T
- High specific for AMI: Considered diagnostic for AMI
- not elevated in renal failure and skeletal diseases.
- not a marker for late AMI
- Onset: 3-4 hours; Elevated: 5-10 days
troponin I
types
- Elevated cTn values >10x the 99th percentile URL in patients with normal baseline cTn values
In patients with elevated preprocedure cTn in whom cTn levels are stable (≤20% variation) or falling:
* the postprocedure cTn must rise by >20%, with absolute postprocedural value >10 times the 99th percentile URL
- Other indicators (at least one): Development of new pathological Q waves, angiographic documented new graft occlusion or new native coronary artery occlusion, or imaging evidence of new loss of viable myocardium/new regional wall motion abnormality in a pattern consistent with an ischemic etiology
type 5 MI
types
- With coronary artery disease
- Detection of a rise and/or fall of cTn values with at least 1 value above the 99th percentile URL
- With at least one of the following criteria: symptoms of myocardial ischemia, new ischemic ECG changes, development of pathological Q waves
- Differential test Type 1-MI and Type 2-MI: Angiography and coronary imaging (imaging evidence of new loss of viable myocardium or new regional wall motion abnormality in a pattern consistent with an ischemic etiology)
- (+) NSTEMI at presentation
type 2 MI
types
- With atherosclerosis and thrombosis
- Detection of a rise and/or fall of cTn values with at least one value above the 99th percentile URL
- With at least one of the following criteria: symptoms of myocardial ischemia, new ischemic ECG changes, development of pathological Q waves, imaging evidence of new loss of viable myocardium, and detection of a coronary thrombus by angiography including intracoronary imaging or by autopsy
- Individuals with ST-segment elevation MI (STEMI) and many with non-ST-segment elevation MI (NSTEMI) are in this category
- Autopsy: Fresh or recent thrombus in the infarct-related artery
type 1 MI
troponin
does not have cardiac specificity since its cardiac isoform is shared by slow twitch skeletal muscles
troponin C
- Govern excitaton-contraction coupling in muscle
- A regulatory complex of three proteins that bind to the thin filaments of striated muscles (skeletal and cardiac muscles).
- These are regulators of actin and myosin.
troponin
conversion factor of troponin T
ng/L to ng/mL: 0.001
are found in largest concentration in the left ventricular myocardium but are also detectable in atrial tissue as well as in the myocardium of the right ventricle
NT-proBNP and BNP
types
- Typical presentation of myocardial ischemia/infarction
- With presumed new ischemic ECG changes or ventricular fibrillation
- Detection of cardiac biomarkers in the blood is fundamental for establishing the diagnosis, however, may not be able to observe the rise in plasma cTn because the patient succumbs (cardiac death) before the onset of symptoms, sample collection, or values are measured
- Patients are designated as having a (?), when suspicion for an acute myocardial ischemic event is high, even when cardiac biomarker evidence of MI is lacking
- With evidence of MI by autopsy
type 3 MI
types
- Focal or diffuse restenosis, or a complex lesion associated with a rise and/or fall of cTn values above the 99th percentile URL
- Same criteria for type I MI is utilized in the diagnosis.
type 4c MI
types
- A subcategory of PCI-related MI
- Vital to indicate the time of the occurrence of the stent/scaffold thrombosis in relation to the timing of the PCI procedure
- Angiography or autopsy using the same criteria for type 1 MI is utilized for diagnosis
type 4b MI
are neurohormones that affect body fuid homeostasis (through natriuresis and diuresis) and blood pressure
natriuretic peptides
troponin
- Three subunits (?), (?), (?)
Clinical Signtficance:
* CTnT or cTnI is used as an (?) indicator because of specificity and early rise in serum concentration
- (?) rises within 34 hours, peaks in 10-24 hours, returns to normal in 10-24 days.
- (?) rises wthin 3-6 hours, peaks in 14-20 hours, and returns to normal in 5-10 days.
- Now known as the “gold standard for diagnosis of (?)”
- troponin T, troponin C, troponin I
- AMI
- troponin T
- troponin C
- MI
