Cardiology Flashcards Preview

Clin Lab > Cardiology > Flashcards

Flashcards in Cardiology Deck (68):
1

What are the 2 branches of the left coronary artery?

-Anterior Descending Coronary Artery
-Left Circumflex Coronary Artery

2

What is the branch of the right coronary artery?

-Posterior Descending Coronary Artery

3

What does the Anterior Descending Coronary Artery supply?

-Anterior septum and left ventricle

4

What does the Left Circumflex Artery supply?

-Anterior and lateral aspects of the left ventricle

5

What does the posterior descending coronary artery supply

-Right ventricle and posterior part of left ventricle

6

This is tissue death with necrosis of the myocardium

Myocardial infarction

7

Characteristics of a STEMI

-Transmural
-Q wave
-All layers of tissue die
-BAD

8

Describe non-STEMI

-Non Q wave
-Subendocardial
-Only the inner most layer dies
-Not as extensive necrosis

9

The EKG changes after an infarct (like a tattoo)

STEMI

10

The full thickness of the heart is affected in....

STEMI

11

This layer is the furthest from the coronaries

Subendocardium

12

If you have a Non-STEMI, what does the EKG look like?

-You cannot tell if the patient ever had a MI

13

Describe the use of a EKG

-Quick
-All electrical activity of 12 different leads

14

What happens to the Q wave after a STEMI

-You get a significant drop in Q wave

15

If a person is currently having a STEMI, what changes on the EKG?

ST elevation (goes away after the STEMI is done)

16

What changes to the EKG does ischemia cause?

-ST depression
-T wave inversion

17

This is a very small protein that enters the blood very quickly, and it is also a muscle oxygen binding protein

Myoglobin

18

Within how many hours is myoglobin detectable?

2-4 hours

19

When does myoglobin peak?

8-12 hours

20

When do myoglobin levels return to normal after a MI?

24-30 hours

21

Describe the sensitivity and specificity of myoglobin

-Very sensitive
-Not specific (because is high during any muscle injury- not specific to myocardial injury)

22

What is the percentage of patients that have abnormal lab tests when they are initially seen in the ER?

25-40%

23

T/F- Normal results should be used to decide whether to discharge a patient from the ER?

FALSEEEEEE

24

This is the major muscle enzyme

Creatinine Kinase

25

Is CK sensitive or specific?

SENSITIVE- due to a large amplitude of change

26

Describe CKs large amplitude of change

They can rise 6-12 times normal

27

What is the sensitivity rate of CK?

98%

28

Does CK have a high false positive rate?

Yes- because there are many causes of increased CK (any type of muscle injury)

29

Where is CK found in high concentrations?

Brain and muscle

30

What are CK levels related to?

-Muscle mass
-Muscle activity

31

Who has high levels of CK?

-Males
-African Americans

32

When are CK levels the highest?

-Weight lifting
-Endurance exercise
-Contact sports

33

Why is it different to create a reference range for CK?

-Wide range of normal CK values (compare the football player to your gramma)

34

What are the 3 CK isoenzymes?

-MM
-MB
-BB

35

Where are CK BB enzyme found?

-Brain
-Prostate
-Placenta
-Fetal Tissue

36

When are levels of CK BB high?

Stroke

37

Where is CK MM found?

Skeletal muscle

38

When is CK MM levels high?

-Trauma
-Falls

39

When are CK MB found?

-Cardiac muscle
-Primarily but not exclusively
-Also associated with skeletal and respiratory muscles

40

What are CK MB levels in a normal individual?

Less than 1% of normal CK

41

What are CK MB levels in a patient with an MI?

Greater than 3% of the total CK in 99% of cases

42

When do CK MB levels begin to rise after an MI

3-6 hours after the onset of a MI

43

When do levels of CK MB peak after an MI?

12-24 hours after MI

44

When do levels of CK MB return to normal after an MI?

24-48 hours

45

Should you do 3 or more sequential samples for tests?

Yes- more frequent sampling is more likely to identify a peak value

46

When should the first blood work sample be drawn from the patient?

Immediately at presentation

47

How many hours should the subsequent tests be run apart?

6 hours during the first 24 hours

48

How is the CK MB index calculated?

CK MB/total CK *100

49

When is CK MB diagnostic of an MI?

If the CK MB index is greater than 3-4%

50

When is the diagnosis of an acute MI confirmed? (hours)

Confirmed by 8-12 hrs

51

Is sampling beyond 24 hours needed?

Not really- except to diagnose early reinfarction

52

How should CK MB be recorded?

CK MB should be reported in unit as well as a percentage because of injury to both cardiac and skeletal muscle
-CK MB percentage/index may not be elevated

53

This is the gold standard test for cardiac troponin

Cardiac troponin

54

Describe cardiac troponin

-Regulatory protein
-Very little floating around at a given time
-Small reference range
-Very sensitive and specific

55

T/F- Cardiac troponin isoforms are completely specific to the myocardium in adults

Cardiac troponin

56

How does depolarization spread through the cell?

Through the T tubules

57

Where is more calcium released from?

Sarcoplasmic reticulum

58

When calcium rises, it binds to

Troponin C

59

Once it binds to troponin C, it changes to the

troponin complex

60

What happens when the tropomyosin is formed?

Causes tropomyosin to be moved out of the way allowing cross binding formation and effective cardiac muscle contraction

61

How can you study troponin even though it is found in skeletal and cardiac muscle

-They are structurally different and can be measured separately by immunoassay

62

Why is troponin highly sensitive?

The plasma ratio is much higher than for enzymes or myoglobin

63

Is cardiac troponin effected by muscle injury?

NOPPPPEEEEEE KIDDDDOOOOO

64

What is the more important measurement of troponin? (Rate of change or the value)

Rate of change

65

How many hours after an acute event do cardiac troponin levels rise?

4-6 hours

66

When does troponin peak?

12 hours

67

How many days can troponin levels be elevated?

7-10 days

68

What is 1 pro and 1 con to a long duration of troponin?

-Provides a longer diagnostic window
-Difficult to recognize reinfarction