acute coronary syndrome

Question 1

define acute coronary syndrome

Answer 1

a subclassification of ischemic heart disease which consists of the conditions:
- unstable angina
- non-ST elevation myocardial infarction (NSTEMI)
- ST-elevation myocardial infarction (STEMI)

Question 2

most common cause of acute coronary syndrome

Answer 2

• rupture of atherosclerotic plaque resulting in thrombus formation in artery

Question 3

what is the rate of artery occlusion in each of the conditions?

Answer 3

unstable angina and NSTEMI - partial occlusion

STEMI - complete occlusion because of thrombus

Question 4

which conditions lead to myocardial necrosis?

Answer 4

STEMI and NSTEMI

Question 5

presentation - the big 5

Answer 5

Smoking
Hypertension
Diabetes mellitus
Hypercholesterolaemia
Family history

Question 6

signs and symptoms

Answer 6

Crushing/pressure-like chest pain that can radiate to the jaw/left arm

Typical symptoms due to reduced CO:
- Breathlessness
- Dizziness
- Weakness

Bilateral leg oedema may present if congestive heart failure (CHF) develops

Question 7

STEMI investigations

Answer 7

ECG – differentiates between NSTEMI and STEMI

Biomarkers of myocyte necrosis
- Troponin T and I
- CK-MB
- Lactate dehydrogenase (outdated due to troponin testing)

Question 8

modifiable risk factors (7)

Answer 8

Hypertension
Hyperglycaemia (DM)
Smoking
Alcohol
Hypercholesterolaemia
Obesity/inactivity
Stress

Question 9

non-modifiable risk factors

Answer 9

Age
Sex (men and post-menopausal women)
Genetic/Family History

Question 10

differentiation on ECG

Answer 10

STEMI - ST elevation
NSTEMI and UA - ST not elevated

Question 11

if someone came in and had ecg showing st long segment what would you do?

Answer 11

automatically make a diagnosis of myocardial infarction and give MONA medication then organise PCI to revascularise the occlusion

Question 12

differentiation on troponin level

Answer 12

UA - no raised troponin
NSTEMI and STEMI - do have raised troponin

Question 13

primary prevention (before ACS has developed)

Answer 13

• Lifestyle advice (e.g. exercise, stop smoking, reduce alcohol, fats and salt, eat more fruit & veg)
• QRISK score
  If above 10%, consider statins
• ACE inhibitor if hypertensive

Question 14

secondary prevention - after a patient has developed ACS

Answer 14

mnemonic - ABAS
- aspirin + antiplatelet 12 months
- Beta-blocker
- ACE inhibitor
- Statin

Question 15

immediate management for acute presentation MI

Answer 15

mnemonic - MONA(C)
- Morphine IV
- Oxygen if low
- Nitrates
- Aspirin 300mg loading dose
- 2nd antiplatelet drug eg - (C)lopidogrel (ONLY IN STEMI)
PCI

NSTEMI
MONA
coronary angiogram either urgently or later, depending on risk

Question 16

STEMI treatment <2hrs MI

Answer 16

percutaneous coronary intervention:
- balloon angioplasty or stenting

IF NOT
thrombolytic therapy
- Promotes plasminogen conversion to plasmin to break down fibrin clots
- First line is Tissue Plasminogen Activator (TPAs)
- Streptokinase is alternative

Question 17

NSTEMI treatment <2hrs MI

Answer 17

• PCI
• thrombolytic therapy not inducated

Question 18

criteria for PPCI for STEMI

Answer 18

ST elevation >2mm in 2 contiguous chest leads or >1mm in 2 contiguous limb leads (ie. territorial)
~Chest pain or other evidence of ischaemia

Question 19

how aspirin works

Answer 19

blocks COX1 in low doses which inhibits thromboxine A2 - inhibits vasoconstriction

blocks COX2 - acts as an antiinflammatory

Question 20

clopidogrel

Answer 20

P2Y12 inhibitor
prevents clotting
pro-drug

Question 21

P2Y12 inhibitors

Answer 21

clopidogrel - pro-drug
prasugrel - not a pro-drug

Question 22

why are PY12 inhibitors given

Answer 22

to prevent clotting - blood thinners

Question 23

drugs - if patients develop complications from MI - for heart failure

Answer 23

milterocorticoid receptor antagonists
implantable cardioverter defibrillator - special pacemaker

Question 24

Complications of MI

Answer 24

• Arrhythmia
• LV failure – pulmonary oedema, cardiogenic shock

Question 25

Acute MI - Definition / diagnosis

Answer 25

Consistent clinical setting for myocardial necrosis PLUS Rise and/or fall in cardiac biomarkers with at least one value >upper reference limit PLUS at least one of: Symptoms of ischaemia New/presumed new ST/T changes or LBBB Development of pathological Q waves Imaging (eg. echo, MR, LV gram) shows new loss of viable myocardium/RWMA Intracoronary thrombus on angiography or autopsy Type 1 MI = Spontaneous plaque rupture, ulceration, erosion, fissure, dissection with intraluminal thrombus

Question 26

unstable angina

Answer 26

- considered to be present in patients with ischaemic symptoms suggestive of an ACS and no elevation in troponins, with or without electrocardiogram changes indicative of ischaemia - however, as a rise in troponins may take some hours it may be indistinguishable for NSTEMI initially and is therefore treated the same until the troponin result is known

Question 27

A 60-year-old man presents with acute chest pain and dizziness. His ECG shows ST elevation in leads II, III, and aVF, and ST depression in leads I and aVL. Which of the following best explains the occurrence of reciprocal ST depression in leads opposite to the infarcted area?

Answer 27

electrical acitivity moving away from the infercted area produces reciprocal changes in opposit leads

Question 28

Why is dual antiplatelet therapy (DAPT) recommended in the management of acute coronary syndromes (ACS), including STEMI?

Answer 28

using 2 antiplatelet drugs such as clopidogrel and aspirin to prevent further clotting in the coronary arteries

Question 29

What is the role of beta-blockers in the acute management of STEMI?

Answer 29

- block the beta-adrenergic receptors in the heart - prevents effects of sympathetic stimulation - involves release of norepinephrine leads to: - red HR - red myocardial contractility - dec BP

Question 30

How does the presence of ST-segment elevation in STEMI affect the urgency of treatment compared to NSTEMI?

Answer 30

ST elevation in STEMI - complete occlusion - full-thickness (transmural) myocardial infarction. NSTEMI - blockage is partial - not full thickness

Question 31

What is the role of angiotensin-converting enzyme (ACE) inhibitors in the management of STEMI?

Answer 31

prevent angiotensin I - angiotensin II effects: - vasodilation - reducing afterload - red fluid retention - low BV - reduce oedema

Question 32

What is the role of statins in the management of STEMI?

Answer 32

HMG-CoA reductase inhibitors: (responsible for cholesterol synthesis) - lowering cholesterol levels - anti-inflammatory effects - improve endothelial function - slows progression of atherosclerosis

Question 33

What is the role of morphine in the acute management of STEMI? (3)

Answer 33

- pain relief - decreased sympathetic response - vasodilation

Question 34

which parts of an ECG correlate with which coronary arteries?

Answer 34

V1-V4 - left anterior descending II, III, aVF - right coronary I, V5-6 - left circumflex