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 plaque rupture affect the endothelium in terms of platelets?

Answer 5

Blood is exposed to sites it doesn’t normally see

Platelets adhere to damaged areas through vWF and collectively form hemostatic plug

Question 6

How does unstable angina differ from stable angina?

Answer 6

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

Question 7

How does angina differ from acute MI?

Answer 7

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

Question 8

What are typical ECG changes that occur in STEMI?

Answer 8

ST elevation
T wave inversion
Q wave formation

Question 9

Why are Q waves “useful”?

Answer 9

Signal that there has been a previous MI

Question 10

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

Answer 10

> 1mm STE in 2+ adjacent limb leads

>2mm STE in 2+ contiguous precordial leads

Question 11

Which leads show STE in an inferior MI?

Answer 11

II, III, aVF

Question 12

Which leads show STE in an anterior MI?

Answer 12

V1-V6

Question 13

Which leads show STE in an anterolateral MI?

Answer 13

I, aVL, V1-V6

Question 14

Which leads show STE in an anteroseptal MI?

Answer 14

V1-V4

Question 15

Which two proteins are used for diagnosing MI?

Answer 15

Troponin T or I

CK enzyme

Question 16

When does CK production peak following an MI?

Answer 16

after 24 hours

Question 17

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

Answer 17

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

Question 18

What is the benefit of troponin T?

Answer 18

Highly specific for cardiac muscle damage

Question 19

Outline immediate treatment of MI

Answer 19

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

Question 20

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

Answer 20

False

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

Question 21

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

Answer 21

Emergency angioplasty

Question 22

What is Dressler’s syndrome?

Answer 22

Post-MI syndrome, occuring weeks after MI

Pleuritic pain, pericarditis, pericardial effusion

Question 23

Could the ECG be normal in acute MI?

Answer 23

YES

Question 24

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

Answer 24

True

Question 25

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

Answer 25

3 months

Question 26

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

Answer 26

True

Question 27

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

Answer 27

4-6 hours

Remain elevated for at least 7 days

Question 28

Name some contraindications to thrombolysis

Answer 28

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