B2.002 Big Case MI Flashcards Preview

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Flashcards in B2.002 Big Case MI Deck (43):
1

What is the principle of Bayesian logic?

The likelihood of a diagnosis depends on the prior probability.

2

Characterize the chest pain relating to angina pectoris/ myocardial infarction

central chest
radiating to left arm/ neck
sever pressure or heaviness

3

List 3 differences between angina and MI.

Angina: precipitated by stress, duration in minutes, relieved by rest
MI: acute onset, unremitting, associated with nausea/vomiting/diaphoresis

4

List groups in order of lowest incidence of MI to highest: white men, black men, white women, black women

white women< black women = white men< black men

5

What is the primary reason for the decrease in CVD over the last 20 years?

Societal changes and resulting increases in prevention

6

When does the heart receive most of its blood supply?

Diastole

7

How does the left ventricular myocardium receive blood?

Coronary arteries during diastole

8

How does the right ventricular/atrial myocardium receive blood?

From the chamber (reptilian)

9

Which part of heart is most susceptible to MI due to occlusion?

Left ventricular myocardium

10

List the heart conduction pathway.

SA node > atrial muscle > AV node > bundle of His > left/right bundle branches > Purkinje fibers > ventricular muscle

11

P wave

atrial depolarization

12

QRS complex

ventricular depolarization

13

ST segment

corresponds to phase 2 of ventricular action potential

14

T wave

ventricular repolarization

15

What are the calcium dependent action potentials/ pacemakers?

SA node, AV node

16

What does it mean to be a pacemaker?

No resting membrane potential

17

What are the sodium dependent action potentials/ nonpacemakers?

atrial myocytes, bundle of His, Purkinje fibers, ventricular myocytes

18

Which part of an ECG is associated with MI?

ST elevation

19

Draw the ventricular action potential and label phases 0-4.

4 flat, 0 sharp rise, 1 sharp downtick, 2 slight linear decrease, 3 quick decrease curve

20

Describe the phases of the ventricular action potential.

Phase 4: stable resting potential
Phase 0: depolarization due to Na current
Phase 1: transient repolarization due to K current
Phase 2: plateau due to balance between Ca and K ions
Phase 3: repolarization phase due to K current

21

Describe phases of SA node action potential.

Phase 4: pacemaker potential where funny sodium current > K current
Phase 0: upstroke of action potential due to Ca current
Phase 3: repolarizing phase where K current > depolarizing currents

22

What is the MDP?

maximum diastolic potential, most negative potential in the SA node, 50 mV

23

How does the slope of phase 4 in the AV node compare to the SA node?

less steep in AV node

24

How does the action potential in the AV node relate to the SA node?

similar shape, same ionic currents, lower intrinsic firing rate

25

How does the atrial action potential compare to the ventricular action potential?

similar shape, same ionic currents

26

What is hypoxia?

Insufficient O2 levels

27

Which step of the action potential is ATP dependent?

L-type calcium channel phosphorylation

28

Which action potential is reduced due to impaired calcium current?

Ventricular

29

How does hypoxia affect ventricular action potential?

insufficient O2 > decreased ATP > impairment of Ca current > decreased duration of action potential

30

How does hypoxia change the action potential graph?

Shorter phase 2/3, appears skinnier

31

What is ischemia?

Insufficient blood flow

32

Ischemia contributes to hypoxia. How else does it affect the action potential?

decreased blood flow > extracellular K accumulation > depolarization of resting membrane potential> resting potential more positive than normal

33

How do hypoxia/ischemia affect ATP production?

decrease

34

How do hypoxia/ischemia affect the inner Na conc?

increase

35

How do hypoxia/ischemia affect the inner K conc?

decrease

36

How do hypoxia/ischemia affect the K-ATP current?

increase

37

How do hypoxia/ischemia affect Ca-L current?

decrease

38

How do hypoxia/ischemia affect outer K conc?

hypoxia doesn't
ischemia increases it

39

How do you detect MI vs. angina?

Presence of biomarkers due to necrosis in MI.

40

What are three results of plaque rupture?

healing, embolism, thrombosis

41

What are the major coronary arteries?

R. Coronary artery and L. Coronary artery

42

What are the branches of the L. Coronary artery?

Circumflex and anterior interventricular (anterior descending)

43

What are the branches of the R. Coronary artery?

anterior r. atrial branch, posterior interventricular (posterior descending)