Ischaemic Heart Disease

Question 1

Ischaemic Heart Disease

Answer 1

a group of clinical syndromes usually due to atherosclerosis of the coronary arteries: angina, MI, heart failure

Question 2

Less common ischaemic heart diseases:

Answer 2

• arrhythmias
• mitral valve dysfunction

Question 3

Angina symptoms and exacerbating figures:

Answer 3

• exertional
• settles within 2-10min
• tight/dull/squeezing/heavy
• poorly localised, L>R, commonly across the chest
• radiation to arms L>R and throat/teeth
• sometimes can be worse on inspiration but very few
• worse: in the cold, after a large meal

Question 4

Demand Ischaemia:
- is (2)
- causes
- when

Answer 4

• stable angina
• fixed obstruction
• inadequate blood flow when demand increases:
  - exertion
  - other demands for blood (post-meal)
  - tachyarrhthmia (increases metabolic demand,
  chest pain)
• will present as chest pain (angina)

Question 5

Incidence of coronary artery disease by age

Answer 5

over 70s increased risk

Question 6

Cardiac Pain:

Answer 6

• referred pain = pain of visceral origin, perceived in
  somatic regions innervated from the spinal segments
  as the heart
• carried via cardiac sympathetic afferent nerves:
  - to spinothalamic tract
  - to the thalamus
  - to the cerebral cortex

Question 7

Cardiac pain referred to which areas?

Answer 7

• T1-T5 (chest pain)
• C5-C6 (shoulder)
• tends to SPARE C7-C8 (distal arm)

Question 8

Cardiac referred pain diagram

Answer 8

insert

Question 9

Myocardial Infarction: symptom of chest pain: key features:

Answer 9

• severe and persistent
• tight/dull/squeezing, heavy
• poorly localised, L>R, commonly across chest
• radiation to arms L>R and throat/teeth

Question 10

Myocardial Infarction associated symptoms:

Answer 10

• malaise
• nausea
• breathlessness
• sweating

Question 11

Myocardial Infarction is acute or chronic

Answer 11

acute

Question 12

Supply Ischaemia:
- is (2)
- caused by
- results in

Answer 12

• acute coronary artery occlusion (full occlusion)
• inadequate blood flow even to cover basal
  requirements
• atheromatous plaque that has ruptured, exposing
  collagen and proteins, activating clotting cascade,
  thrombus formation, looming occlusion
• results in an acute MI

Question 13

Ischaemic Cascade:

Answer 13

insert diagram

Question 14

Heart Failure:
- causes and symptoms

Answer 14

• Due to low cardiac output:
  - fatigue
• Due to fluid retention:
  - leg swelling
  - breathlessness (cough)
  - orthopnoea
  - Paroxysmal nocturnal dyspnea (waking in the
  night gasping for breath)
• 50-70% cases due to IHD:
  - previous MIs
  - chronic ischaemia

Question 15

Paroxysmal nocturnal dyspnea indicates

Answer 15

LV systolic dysfunction

Question 16

Silent Ischaemia:

Answer 16

• first sign of IHD may be sudden death:
  - acute occlusion of non-obstructive plaques or
  - obstructive disease with silent ischaemia
• strong evidence of benefit from preventive
  medication/therapies and lifestyle changes

Question 17

Silent Ischaemia: Screening?:

Answer 17

• no ideal screening test
• Exercise ECG: low sensitivity and specificity, labour
  intensive
• Cardiac CT: expensive, radiation risk

Question 18

Principles of Management for all IHD patients:

Answer 18

• lifestyle changes
• risk factor management
• anti-thrombotic therapy

may work:

• medication for symptoms
• revascularisation for chronic, severe disease
• acute reperfusion Rx for STE-MI
• rehabilitation

Question 19

Principles of Management for IHD: Lifestyle changes:

Answer 19

• stop smoking
• optimise weight: MBI 18.5-25 kg/m^2
• low saturated fat diet
• regular aerobic exercises

Question 20

Principles of Management for IHD: Risk Factor Management: State the three risk factors:

Answer 20

• hypertension
• hyperlipidaemia
• diabetes
• become younger and more female

Question 21

Principles of Management for IHD: Risk Factor Management: Hypertension:

Answer 21

• lose weight
• reduce salt intake
• drugs (ACE inhibitors = Ramipril)

Question 22

Principles of Management for IHD: Risk Factor Management: Hyperlipidaemia:

Answer 22

• diet: reduce saturated fat intake
• Drugs: (statins = atorvastatin)

Question 23

Principles of Management for IHD: Risk Factor Management: Diabetes:

Answer 23

• optimise glycaemic control: reduce intake of refined
  sugars
• drugs (metformin, insulin)

Question 24

Anti-platelet drugs:

Answer 24

• cyclo-oxygenase: aspirin
• ADP receptor anatagonist: Clopidogrel
• GP 2b/3a antagonists: Abciximab, Tirofiban,
  eptifibatide

Question 25

Anti-platelet drugs diagram

Answer 25

insert

Question 26

Acute MI anticoagulants:

Answer 26

- heparin derivatives - intravenous heparin - low molecular weight heparin - fondaparinux

Question 27

Anti-anginals:

Answer 27

- beta blockers (beta 1 selective (bisoprolol)) - calcium channel antagonists (cause vasodilation) (amlodipine, diltiazem) -

Question 28

Anti-anginals:

Answer 28

- beta blockers (beta 1 selective (bisoprolol)) - calcium channel antagonists (cause vasodilation) (amlodipine, diltiazem) - Nitrates (GTN, isosorbide)

Question 29

Medical Rx - Anti-anginals: beta-blockers:

Answer 29

- block cardiac beta-1 receptors: reduce the force of contraction, reduce heart rate response to exercise - biosprolol (beta 1 selective)

Question 30

Medical Rx - Antianginals: Calcium Channel Blockers:

Answer 30

- calcium channel antagonists - reduce calcium entry to myocyte and vsacular smooth muscle - reduce force of heart contraction - dilate arteries: coronary arteries, lowers BP (reduced afterload) - amlodipine, diltiazem

Question 31

Medical Rx - anti-anginal drugs: Nitrates:

Answer 31

- nitrates mimic actions of nitric oxide (EDRF) - dilate coronary arteries - dilate veins > arteries, reducing venous return (preload) - short-acting: GTN spray - Long acting: Isosorbide mononitrate

Question 32

Left anterior descending artery:%:

Answer 32

45%

Question 33

Circumflex artery: %:

Answer 33

20-30%

Question 34

Left mainstem and Proximal Left anterior descending:

Answer 34

high risk

Question 35

Revascularisation: Coronary Artery Bypass Grafting:

Answer 35

- open heart surgery via sternotomy - uses conduits to bypass coronary stenoses: internal mammary arteries, radial arteries, saphenous veins - heart stopped - bypass machine - 1 week in hospital - 2-4 months recovery

Question 36

Revascularisation: PCI:

Answer 36

- percutaneous coronary intervention - stenting, angioplasty - percutaneous procedure: - catheter to the coronary artery - wire through the narrowing - dilated with a balloon - stent deployed - local anaesthetic - rapid recovery - home same day - back to normal in 1 week

Question 37

Acute MI: minutes = myocardium:

Answer 37

- necrosis detectable after 15min, but - not uniform within an ischaemic territory: sub- endocardial myocardium is more sensitive, collateral blood vessels provide partial protection - myocardium can be salvaged upto 12 hours after coronary occlusion

Question 38

Acute reperfusion Rx for ST-elevation MI- thrombolysis vs primary PCI:

Answer 38

Typical STEMI mortality rates: Pre-intervention 10-15% Thrombolysis/aspirin 6-8% Balloon only PCI 2-3% Balloon + stenting PCI <1%

Question 39

Why is it harder to use a saphenous vein in a CABG?

Answer 39

harder to make a vein behave as an artery 7% occlusion chance