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Flashcards in Cardiac Enzymes Deck (30)
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1

How do you distinguish between a STEMI and NSTEMI?

EKG

2

How do you distinguish between UA and NSTEMI?

Cardiac Enzymes

3

What are cardiac enzymes?

When there is an infarction of myocardial cells the membrane integrity is disrupted causing leaking of macromolecules into the peripheral circulation where they are detected.

4

Ideal Biomarker Requirements:

- High Specificity
- High Sensitivity
- Release and Clearance kinetics provide expedient diagnosis
- Measured level is in direction proportion to the extent of myocardial injury
- Commercially available, easy to perform

5

This cardiac enzyme is highly specific and sensitive for MI.

It will rise in 3-12 hours
Peak at 24 hours
Return to normal in 5-14 days

Troponin I

6

This cardiac enzyme is highly specific and sensitive for MI.

It will rise in 3-12 hours
Peak at 12-48 hours
Return to normal in 5-14 days

Troponin T

7

When are troponin levels more beneficial?

6+ hours post-MI

8

When do you need to reassess Troponin?

6-12 hours after symptoms began

9

T/F: Troponin levels are not useful for late diagnosis of MI

False, they are useful.

10

Negative Troponin Test indicates:

Low Risk of Death or MI within 30 days

11

Positive Troponin Test indicates:

Strong Independent Predictor of Mortality and Serious Adverse Outcomes

12

Tropinin turn around time?

9-12 minutes

13

If a patient comes in with ACS symptoms, regardless of EKG findings, if there are negative troponins at least twice, how would we categorize this?

Unstable Angina

14

If a patient comes in with ACS symptoms, ST/T Abnormalities (not Elevation) EKG findings, if there are positive troponins at least once, how would we categorize this?

NSTEMI

15

Causes of Troponin Elevation other than MI

- CHF
- Tachyarrhythmia, heart block
- Endurance Exercise
- Cardiomyopathy (CM)
- Myocarditis, Pericarditis
- Blunt Chest Trauma
- Pulmonary Embolism
- Renal Failure
- Severe Sepsis
- Aortic Valve Disease
- CVA
- Cardiotoxic Drugs

16

This enzyme is found in multiple places throughout the body, including: brain, lungs, GI, skeletal and cardiac muscle. It is subdivided into different groups.

Normal Range:

Creatine Kinase

17

CK found in brain, lungs, and GI

CK-BB

18

CK found predominantly in cardiac muscle and some skeletal muscle

CK-MB

19

CK found in skeletal and cardiac muscle

CK-MM

20

______ of CK increases diagnostic specificity.

Fractionation

21

This is the most specific of the CKs for cardiac muscle.

It rises in 3-12 hours
Peaks at 24 hours
Returns to Baseline in 2-3 days

CK-MB

22

False Positives of CK-MB could be due to

- Trauma
- Skeletal Muscle Injury
- Surgical Procedures

23

What is better than CK-MB testing the same thing?

Monoclonal Antibody Assays (More accurate)

24

How do you calculate the Relative Index for CK-MB?

[Measure CK-MB (ng/mL) x 100]/Total CK Activity (IU/L)

25

What is the point of calculating the Relative Index?

Can assist in differentiating False Positives

26

Rule of Thumb to determine if Postiive CK-MB is due to skeletal muscle damage or not?

A ratio of less than 3 is consistent with a skeletal muscle source.

27

A Relative Index > 5 would indicate what?

Myocardial Necrosis

28

This cardiac enzyme is a low molecular heme protein found in cardiac AND skeletal muscle.

It rises in 1-4 hours
Peaks in 6-7 hours
Returns to normal within 24 hours.

HIGHLY Sensitive to MI, but NOT specific

Myoglobin

29

False Positives of Myoglobin could be due to:

- Skeletal Muscle Injury
- Trauma
- Renal Failure

30

Which two tests are no longer recommended for MI?

Doubt we need to know this.

LDH
AST