8. IHD

Question 1

What is Ischaemic Heart Disease? Which conditions does it include?

Answer 1

Disease of the coronary arteries affecting oxygen supply to myocytes.

Includes:

1. stable angina
2. unstable angina
3. non-ST elevation myocardial infarction (NSTEMI)
4. ST elevation myocardial infarction (STEMI)

Question 2

What is Acute Coronary Syndrome? Which conditions does it include?

Answer 2

Acute myocardial ischaemia usually caused by atherosclerotic coronary artery disease.

Includes:

1. unstable angina
2. NSTEMI
3. STEMI

Question 3

What is the difference between the different types of IHDs?

Answer 3

1- Unstable angina - heart tissue ischaemia occurs only when myocardium metabolic demands are greater than what can be delivered via coronary arteries (e.g. during exercise)

2- Stable angina - persistent heart tissue ischaemia

3- NSTEMI - heart tissue death (infarction) due to ischaemia

4- STEMI - heart tissue death (infarction) due to ischaemia, with increased spectrum of occlusion

Question 4

What is the main cause for IHD?

Answer 4

Atherosclerosis: fat builds up over time, forming atheroma in the coronary arteries - lipid-laden core with a fibrous external cap.

Question 5

What is the difference in pathophysiology between stable angina and Acute Coronary Syndrome diseases?

Answer 5

Stable angina - stable atherosclerotic plaque

ACSs - atherosclerotic plaque ruptures

Question 6

Describe the pathophysiology of Acute Coronary Syndrome.

Answer 6

i) Atherosclerotic plaque ruptures.
ii) Platelet aggregation… thrombus formation.
iii) Partially occluded lumen becomes increasingly occluded.
iv) Ischaemia and myocyte necrosis.

Question 7

In addition to atherosclerosis, suggest possible causes for stable angina.

Answer 7

1. coronary artery stenosis
2. coronary artery spasms
3. anaemia
4. severe aortic valve stenosis ( causing reduced CO and heart overexertion )
5. hypertrophic cardiomyopathy ( too much muscle for coronary supply )
6. severe hypertension with LV hypertrophy - less typical

Question 8

What is the difference between type I and type II MI?

Answer 8

Type I - spontaneous MI (most common)
- atherosclerosis

Type II - secondary to ischaemia imbalance

1. coronary spasms
2. coronary dissections
3. aortic root dissection
4. mechanical obstruction during cardiac intervention

Question 9

What is the difference in pathophysiology of NSTEMI and STEMI?

Answer 9

NSTEMI usually due to: acutely progressive tight stenosis of coronary artery - causes partial thickness damage of heart muscle

STEMI usually due to: acute total occlusion of major coronary artery - causes full thickness damage of heart muscle

Question 10

Describe the type of pain experienced in stable angina.

Answer 10

i) dull, central/retrosternal pain, may get radiation
ii) triggered by exertion, completely relieved by rest
iii) GTN spray relieves pain
iv) otherwise well

Question 11

Describe the type of pain experienced in unstable angina.

Answer 11

i) dull, central/retrosternal pain, may get radiation

ii) pain occurs at rest, may be more intense and may last longer than in SA

Question 12

Describe the type of pain experienced in myocardial infarction.

Answer 12

i) dull, central/retrosternal pain, often pressure/heaviness
ii) often radiates to jaw, neck or shoulders
iii) pain occurs at rest, is much more severe than angina and is ongoing >15 min
iv) no alleviating factors

Question 13

As well as pain, what signs/symptoms will a patient with MI show?

Answer 13

Looks unwell, features of increased ANS input: sweating, pallor, nausea

Question 14

Name 3 non-modifiable risk factors for IHD.

Answer 14

1. advanced age
2. family history
3. male gender

Question 15

Name 6 modifiable risk factors for IHD.

Answer 15

1. smoking
2. hypertension
3. hypercholesterolaemia
4. diabetes
5. obesity
6. sedentary lifestyle