Acute Coronary Syndromes

Question 1

What change/event in the atherothrombotic process can lead to ACS (MI, stroke, unstable angina)?

Answer 1

Plaque rupture consequently occluding critical areas (coronary artery)

Question 2

Describe chronic/stable angina

Answer 2

Fixed stenosis due to atheroma limits blood flow
Pain on exertion, relieved by rest/GTN spray

Question 3

What are the 3 (main) acute coronary syndromes?

Answer 3

Unstable angina
NSTEMI
STEMI

Question 4

What factors favour plaque rupture?

Answer 4

Thin fibrous cap
Sudden intraluminal pressure changes
High lipid content of plaque

Question 5

How does unstable angina differ from stable angina?

Answer 5

Pain caused by less and less exertion, in some cases eventually at rest
GTN becoming less effective

Question 6

How does angina differ from acute MI?

Answer 6

Shorter (10 mins vs. 30 mins)
Pain on exertion (vs. rest)
GTN relief (vs. no relief)

Question 7

What are typical ECG changes that occur in STEMI?

Answer 7

ST elevation
T wave inversion
Q wave formation

Question 8

Why are Q waves “useful”?

Answer 8

Signal that there has been a previous MI

Question 9

What characteristics must the ST elevation have in order to diagnose STEMI?

Answer 9

> 1mm STE in 2+ adjacent limb leads
2mm STE in 2+ contiguous precordial leads

Question 10

Which leads show STE in an inferior MI?

Answer 10

II, III, aVF

Question 11

Which leads show STE in an anterior MI?

Answer 11

V1-V4

Question 12

Which leads show STE in an anterolateral MI?

Answer 12

I, aVL, V3-V6

Question 13

Which leads show STE in an anteroseptal MI?

Answer 13

V1-V4

Question 14

Which two proteins are used for diagnosing MI?

Answer 14

Troponin T or I
CK enzyme

Question 15

When does CK production peak following an MI?

Answer 15

after 24 hours

Question 16

Why is CK not commonly used solely anymore to diagnose MI?

Answer 16

Also present in skeletal muscle and brain, so elevated levels could be due to injury in these areas

Question 17

What is the benefit of troponin T?

Answer 17

Highly specific for cardiac muscle damage

Question 18

Outline immediate treatment of MI

Answer 18

diaMorphine
Oxygen if hypoxic
Nitrate (GTN) if BP >90
Aspirin
Clopidogrel
PCI within 90 mins, or else thrombolysis

Question 19

If PCI cannot be given within 60 mins of seeing STEMI on ECG, do thrombolysis. True/False?

Answer 19

False
If PCI cannot be given within 90 mins (incorporating 40min drive time), then do thrombolysis

Question 20

If a patient fails to improve following thrombolysis, what is done?

Answer 20

Emergency angioplasty

Question 21

What is Dressler’s syndrome?

Answer 21

Post-MI syndrome, occuring weeks after MI
Pleuritic pain, pericarditis, pericardial effusion

Question 22

Could the ECG be normal in acute MI?

Answer 22

YES

Question 23

In unstable angina, troponins may be normal. True/False?

Answer 23

True

Question 24

In a patient with a bare metal stent, how long should clopidogrel therapy last?

Answer 24

3 months

Question 25

Cardiac troponin levels are negligible in healthy people. True/False?

Answer 25

True

Question 26

How long does it take for cardiac troponin levels to increase? How long do they remain elevated?

Answer 26

4-6 hours
Remain elevated for at least 7 days

Question 27

Name some contraindications to thrombolysis

Answer 27

Trauma, haemorrhage
Recent surgery (within 2wks)
Recent stroke (within 6mths)
Severe hypertension
Active peptic ulcers