Ischaemic Heart Disease

Question 1

What are 4 CVS diseases/problems that atherosclerotic coronary disease can cause?

Answer 1

Chronic coronary insufficiency
- angina
Unstable coronary disease
- MI
- sudden ischaemia
Heart failure
Arrhythmias

Question 2

What is an epicardial coronary artery? Give one example of an epicardial coronary artery.

Answer 2

Coronary artery that lies on the outer surface of the heart
Examples:
- LAD
- Circumflex
-

Question 3

Where therefore does an endocardial coronary artery lie?

Answer 3

Inner surface of the heart

Question 4

What is the subendocardial region?

Answer 4

Water-shed area of perfusion and first to become ischaemic

Question 5

What are the 3 most commonly used types of coronary artery imaging?

Answer 5

Coronary angiography
CT
MRI (measures flow)

Question 6

List some of the risk factors of coronary artery disease.

Answer 6

Smoking
Age
Hypertension
Hypercholesterolaemia
Diabetes
Obesity
Physical inactivity

Question 7

What are the 3 main stages in coronary artery disease pathological development?

Answer 7

Fatty streak formation
Fibro-fatty plaque formation
Plaque disruption (rupture/erosion)

Question 8

How do foam cells form?

Answer 8

Monocytes migrate out of the blood to form macrophages and set about ingesting the fat, forming foam cells

Question 9

What chemical mediator release stimulates the aggregation of smooth muscle cells?

Answer 9

Cytokine release

Question 10

What are some of the symptoms of angina?

Answer 10

o Gripping central chest pain
o Radiation to arm and jaw
o Clear and precise relationship to exercise
o Goes 2-10 mins after discontinuation of exercise
o Worse after food. Worse in cold
o No autonomic features
o Flat of hand/fist to describe pain

Question 11

What is the cause of angina?

Answer 11

Sub-endocardial ischaemia

Question 12

What abnormality is present on an ECG in cases of angina?

Answer 12

ST wave depression

Question 13

What is a key issue in cases of epicardial stenosis?

Answer 13

Mismatch of blood supply and demand

Question 14

What are the two coronary flow regulatory mechanisms?

Answer 14

Auto regulation

Metabolic regulation

Question 15

In order to a 20 fold increase in total body O2 consumption, by how much can coronary blood flow increase?

Answer 15

5 fold

Question 16

What does the Adenosine Hypothesis of Coronary Dilation state?

Answer 16

ATP –> AMP – 5-nucleotidase –> adenosine – ADA –> Inosine

Question 17

What are the 3 main determinants of myocardial oxygen consumption?

Answer 17

Tension development (variable per unit mass of tissue)
Contractility (variable)
Heart rate (variable)
Basal activity (fixed)

Question 18

What is the function of angina treating drugs?

Answer 18

Reduce myocardial oxygen consumption

Question 19

What are two other more invasive treatments of angina?

Answer 19

PCI - Percutaneous Coronary Intervention (stents & balloons)
CABG - Coronary Artery Bypass Grafting

Question 20

List the 4 classes of drug used in angina treatment.

Answer 20

Beta blockers
Nitrates
Calcium channel blockers
Ikf channel inhibitors

Question 21

What physiological impact do beta blockers have on the CVS?

Answer 21

Reduce BP
Reduce HR
(hence reduce work of heart)

Question 22

What do nitrates cause in the CVS?

Answer 22

Venodilation –> reduces LV wall tension –> reduced work of the heart

Question 23

What physiological impact do calcium channel blockers have on the CVS?

Answer 23

Decrease HR

Question 24

What is the MOA of Ikf channel inhibitors?

Answer 24

Inhibit channels in the SA node –> decrease HR

Question 25

Which vessel is most appropriate for grafting in place of the RCA?

Answer 25

Saphenous vein

Question 26

Which vessel is most appropriate for grafting in place of the LAD?

Answer 26

LIMA - Left internal mammary artery

Question 27

What percentage of MI sufferers do not make it to hospital?

Answer 27

15 - 20%

Question 28

What is MI mortality in hospital?

Answer 28

6 - 15%

Question 29

What is the clinical presentation of MI?

Answer 29

Severe chest pain radiating to jaw and arm (generally left) Autonomic symptoms inc. nausea, sweating, terror, etc. Breathlessness

Question 30

What are the 2 main causes of MI?

Answer 30

Plaque rupture | Plaque erosion

Question 31

List 5 events that can modify MI presentation.

Answer 31

``` o Time of day o Inflammatory activity o Infection, especially respiratory o Elevation of blood pressure o Catacholamines ```

Question 32

What are the 2 main types of MI?

Answer 32

STEMI | NSTEMI

Question 33

How can an MI be clinically diagnosed?

Answer 33

Raised cardiomyocyte markers in blood (TROPONIN I/T) Clinical history For STEMI: ST elevation in ECG

Question 34

Outline the treatment plan for a STEMI.

Answer 34

First... - Antiplatelet agents: Aspirin + Clopidogrel - Immediate revascularisation, i.e. primary PCI or thrombolysis (- clot busting) Then... - Beta blockers (reduce myocardial infarction) - Statin drugs (reduce cholesterol – plaque passivation) - ACE inhibitors (usually a couple of days later to inhibit dilation of the left ventricle)

Question 35

What are two complications of STEMI's that can occur immediately?

Answer 35

Ventricular Arrhythmia and death | Acute Left Heart Failure

Question 36

What are two complications of STEMI's that can occur early on?

Answer 36

Myocardial Rupture Mitral valve insufficiency Ventricular Septal defect Mural thrombus and emobolisation

Question 37

What are two complications of STEMI's that can occur later on?

Answer 37

LV dilatation and heart failure Arrhythmia Recurrent myocardial infarction

Question 38

In which age group is NSTEMI most prevalent?

Answer 38

The elderly

Question 39

What is a common cause of NSTEMI and therefore can be implied?

Answer 39

Sub-endocardial ischaemia

Question 40

What 4 CVS events can predispose to NSTEMI occurrence?

Answer 40

Threatened STEMI Small branch occlusion Occlusion of well collateralised vessel Lateral STEMI in territory not well seen by ECG

Question 41

Outline the treatment plan for an NSTEMI

Answer 41

Antiplatelet therapy (Aspirin and clopidogrel) Anti-ischaemics (beta blockers and nitrates) Statin drugs ACE inhibitors Coronary angiography and revascularisation ---> Early if symptoms continue ---> Early if Troponin raised ---> Risk score (e.g. GRACE)