14) Cardiac function Flashcards
1
Q
Biochemical feature or facet that can be used to measure the progress of disease or the effects of treatment.
A
biomarker
2
Q
Greek for gruel and refers to the massive accumulation of lipids in these vascular lesions.
A
athero
3
Q
Was considered to be a bland lipid storage disease
Now thought to evolve from the inflammatory process
A
Atherosclerotic vascular disease (ASVD)
4
Q
Acute coronary syndrome (ACS)
A
Described as a continuum of clinical signs and symptoms ranging from…
unstable angina (chest pain) to…
non-Q-wave (ECG pattern) acute myocardial infarction (AMI) and Q-wave AMI.
5
Q
most common cause of ASC
A
atherosclerosis in coronary arteries
6
Q
Locally acting autacoid polypeptides that mediate vasoconstriction by interacting with phospholipase C-linked receptors.
Released early in the inflammatory response preceding an ACS.
A
cytokines
7
Q
Double-walled sac that encloses the heart
A
pericardium
8
Q
Made up of cardiac muscle
Anchored to the heart’s fibrous skeleton
A
myocardium
9
Q
Connective tissue and squamous cells make up the internal lining of the myocardium
A
endocardium
10
Q
Deposition of tough, rigid collagen inside the vessel wall and around the atheroma
A
arteriosclerosis
11
Q
Most common form of arteriosclerosis
Caused by the formation of multiple plaques within the coronary arteries
A
atherosclerosis
12
Q
Results from the accumulation of atheromatous plaques within the walls of the arteries that supply the myocardium
A
CAD
13
Q
cardiac biomarker release affected by…
A
- Cytosolic enzymes
- Subcellular location
- Molecular mass
- Plasma clearance
- Concentration gradients
14
Q
Layering or gradation of risk factors, which are described as elements or constituents that may put someone’s health in peril
A
risk stratification
15
Q
Many cardiac biomarkers are used for evaluating….
A
risk stratification
16
Q
characteristics of ideal cardiac biomarkers
A
- Smaller markers are released faster from injured tissues.
- Soluble cytoplasmic marker is preferred to structural markers.
- Have absolute cardiac tissue specificity and should not exist in other tissues.
- Useful to differentiate between reversible (ischemic) and irreversible (necrotic) damage.
- Release from the myocardium should be complete following injury.
- Amount of marker released should be in direct proportion to the size of the injury (infarct sizing).
- Remain elevated long enough (12 to 24h) to be detected in the serum of the “late presenter.”
- For risk stratification, there should be a correlation between outcome and the presence or absence of a marker in serum or the degree of elevation of the marker above “normal.”
- Should be cleared rapidly to allow diagnosis of recurrent injury.
- Should be useful for monitoring of reperfusion and re-occlusion.
- Assays should be relatively easy and quick to perform.
17
Q
Regulatory protein of the myofibril
A
troponin
18
Q
3 troponins and their functions
A
- Troponin I—Binds to actin and inhibits contraction
- Troponin T—Binds tropomyosin
- Troponin C—Contains 4 Ca-binding sites & regulates contraction
19
Q
Two isoforms of TnI
Several isoforms of TnT
A
skeletal muscle
20
Q
One isoform of TnI
Several isoforms of TnT
A
cardiac muscle
21
Q
Binds to actin and inhibits muscle contraction
A
cTnI
22
Q
Binds tropomyosin
A
cTnT
23
Q
Has 3 isoforms, one of which has unique cardiac specificity
A
cTnI
24
Q
Isoform can be demonstrated in patients with muscular dystrophy, polymyositis, and end-stage renal disease.
A
cTnT
25
(cTnI/cTnT) is NOT expressed in skeletal muscle.
cTnI
26
what makes troponins good cardiac biomarkers?
* High level of diagnostic specificity and sensitivity.
* Possess early release kinetics after an AMI
* Remain elevated for a long interval of time
* Very low to undetectable concentrations in serum from healthy patients
* Relatively few interfering substances
27
Drawing blood samples periodically, usually at prescribed time intervals over the course of the patient's admission
serial sampling
28
**Total CK**
rise
peak
return to normal
4-6 hours
24 hours
3-4 days
29
**CK-MB**
rise
peak
return to normal
4 hours
18 hours
2 days
30
**Myoglobin**
rise
peak
return to normal
1-3 hours ★ (earliest)
8-12 hours
1 day
31
**TnT**
rise
peak
return to normal
4-6 hours
10-24 hours
10 days ★ (longest)
32
**TnI**
rise
peak
return to normal
4-6 hours
10-24 hours
4 days
33
sources of error for cTnI
**False positive**
Heterophile antibodies
Rheumatoid factor
**False negative**
Bilirubin
Hemoglobin
Circulating cTnI autoantibodies
Interfering factor (IF)
| do not affect TnT
34
causes of elevated troponins besides ACS
* Trauma
* HTN
* Hypotension, often with arrhythmias
* CVA
* Rhabdomyolysis (cardiac)
* Cocaine-induced rhabdomyolysis
* Post-op noncardiac surgery
* Renal failure
* DM
* Burns
* Severe asthma
* Sepsis
35
WHO criteria for making AMI dx and European revisions
1. History of characteristic chest pain
2. Diagnostic changes in the EKG
3. Changes in serum enzyme levels
**Revisions**
1. Promote troponin to a pivotal role
2. Relegate CKMB to a secondary role
3. Eliminate the need for CK
36
non-cardiac CKMB elevations
* Severe skeletal muscle injury following trauma or surgery (ie crushing injury)
* Chronic muscle disease in patient with muscular dystrophy, end-stage renal disease, or polymyositis
* Healthy people who exercise and participate in physical activity such as long-distance running
* Extensive rhabdomyolysis
* Early dermatomyositis
37
CK index
CKMB(100)/total CK
| do not use if total CK is normal
38
CK index >5%, <5%, and RR
>5% — MI
<5% — crushing injury
RR — <3%
39
First cardiac biomarker to appear in circulation that may be used for assessment of ACS.
myoglobin
40
myoglobin may be pos for...
MI or crushing injury
41
myoglobin advantages
* High sensitivity and negative predictive value
* Useful for early detection of MI and reperfusion
42
myoglobin disadvantages
* Low specificity in presence of skeletal muscle injury and renal insufficiency
* Rapid clearance after necrosis
* Labor-intensive process on urine; doesn’t make very much sense to run as an early detection marker
43
mainly expressed in the heart ventricles, discovered in porcine brain
BNP
44
pathway of BNP synthesis
* Initially synthesized as **preproBNP** (134 amino acids)
* Cleaved into **proBNP** (108 aa)
* Cleaved again into **NT-proBNP** (76 aa) and **BNP** (32 aa)
45
part of the body’s defense against volume overload and hypertension
BNP
46
BNP functions
Dilate blood vessels
Increase the excretion of sodium and fluids
Reduce concentrations of neurohormones (ie. ADH) that lead to:
* Vessel constriction
* Fluid retention
* Elevated blood pressure
47
Elevated plasma ----- indicates the presence of heart failure and provides information about its severity.
NT-proBNP
48
Heart is unable to pump sufficient blood to meet body’s metabolic needs and normal filling pressure.
CHF
49
2 types of CHF
Diastolic — heart cannot fill properly
Systolic — heart cannot contract/pump properly
50
s/s of CHF
Dyspnea
Increased fatigue
Edema
51
best biomarkers for CHF
BNP/NT-proBNP
52
essentially obsolete cardiac biomarker due to lack of tissue specificity
LD
53
found in high concentrations in the heart, kidney, and erythrocytes
LD-1
54
Nonspecific, acute-phase reactant. Shows up during inflammatory processes.
CRP
55
Measuring blood levels of hs-CRP provides better ..... than measuring any other biomarker.
risk assessment of cardiovascular disease
56
Produced when circulating albumin comes in contact with ischemic tissue in the heart or other organ.
Ischemia-Modified Albumin (IMA)
57
Albumin cobalt binding test
used to measure IMA
Cobalt is added to serum and **does not bind to ischemia-modified albumin**, thus leaving more free cobalt to react with the reagent dithiothreitol
58
Secreted by activated leukocytes
Enriched in unstable atherosclerotic lesions.
myeloperoxidase
59
Elevated results are seen in patients with AMI (>50 ng/mL).
myeloperoxidase
60
Myeloperoxidase is useful for both short- and long-term ...... and may help identify ...... at risk for major adverse cardiac events.
risk stratification for CVD
troponin-negative patients
61
This has shown to be a good indicator of cytokine storm syndrome (CSS) severity and mortality risk in COVID-19 positive patients.
IL-6
62
Typically measured during pregnancy to detect Down syndrome.
Pregnancy-Associated Plasma Protein-A (PAPP-A)
63
A zinc-binding metalloproteinase and insulin like growth factor (IGF).
Pregnancy-Associated Plasma Protein-A (PAPP-A)
64
Increased circulating PAPP-A is associated with ------
ACS
65
Found primarily in the fatty plaques that may line the walls of coronary arteries in patients with atherosclerosis
oxidized LDL
66
Circulating levels of ------ are strongly associated with angiographically documented CAD in patients 60 years of age or younger.
Ox-LDL
67
Includes the recruitment of circulating macrophages into atherosclerotic lesions and **stimulation of smooth muscle cell growth**
Appears to function in the **early stages of the inflammatory process**
Placental Growth Factor (PlGF)
68
May serve as a strong candidate biomarker for plaque instability, myocardial ischemia, and patient prognosis in ACS
Placental Growth Factor (PlGF)
69
In the heart, participates in vascular remodeling, plaque instability, and ventricular remodeling after cardiac injury.
Matrix Metalloproteinase-9
70
Is released into the circulation when the myocardium is injured
low specificity in the presence of skeletal muscle injury and renal insufficiency
Heart-Type Fatty Acid-Binding Protein (H-FABP)
71
may provide a sensitive guide to the underlying pathophysiology of coronary heart disease.
FFAU
72
FFAU
fatty acids unbound to albumin
73
How do omega-3 FAs reduce risk of CVD?
* Decrease risk for arrhythmias
* Decrease risk for thrombosis
* Decrease triglycerides and remnant lipoprotein levels
* Decrease rate of growth of the atherosclerotic plaque
* Improve endothelial function
* Slightly lower blood pressure
74
Produced by macrophages and expressed in atherosclerotic lesions
enzyme that co-traffics with LDL in circulation
Lipoprotein-Associated Phospholipase A2 (Lp-PLA2)
75
Biological function is unclear.
Roles may be to:
* Respond to tissue injury and vascular lesions
* Prevent infectious pathogens from invading cells
* Promote wound healing
Lipoprotein (a)
76
Most important role in atherothrombosis is to inhibit clot formation at site of injury.
Lp (a)
77
Competes with plasminogen for binding sites thus interferes with clot lysis and increases the risk of AMI
Lp (a)
78
Screen for ------- if there is a(n):
* Family history of premature CVD
* Family history of hyperlipidemia
* Established CVD with normal routine lipid profile
* History of recurrent arterial stenosis
Lp (a)
79
Plasma -------- levels may predict cardiovascular events years in advance in a population without diagnosed CVD.
adiponectin
80
High blood levels are associated with reduced risk of heart attacks.
Low blood levels are found in individuals who are obese, and who are at increased risk.
adiponectin
81
Causes vasodilatation
Plays a role in fat metabolism and obesity
leptin
82
The higher the blood leptin level, the -------- the risk of developing CVD.
greater
83
found to have an independent protective association with unstable CAD
leptin
84
advantages of cardiac POC
* Rapid identification of AMI
* Decreased turn-around time for analysis
* Rapid exclusion of ACS
* Rapid stratification of cardiac patients
* Rapid identification and exclusion of CHF
