Ischaemia and Infarction

Question 1

What is low flow infarction?

Answer 1

Low flow infarction occurs in cardiovascular shock when blood lost due to trauma leads to insufficient blood being pumped to the tissues.

Question 2

What are the 3 most significant causes of ischaemia?

Answer 2

Atheroma, Thrombosis, Embolism

Question 3

Why will vasculitis lead to acute ischaemic damages?

Answer 3

Inflamed vessels tend to thrombose. Hence, thrombosis may occur, leading to ischaemic damages

Question 4

What is the cause of Raynaud’s disease?

Answer 4

Spasm of blood vessels leads to ischaemia.

Question 5

What is Cryoglobulinaemia?

Answer 5

A medical condition where the blood carries large amounts of cryoglobulin - proteins that becomes insoluble at reduced temperatures

Question 6

Define cardiac sudden death

Answer 6

An unexpected death due to heart problems that occur within 1 hour from the start of any cardiac related symptoms.

Question 7

What are the 2 possible causes of cardiac sudden death?

Answer 7

Massive Transmural acute myocardial infarction and fatal arrhythmia (eg. VF)

Question 8

Define angina pectoris

Answer 8

Paroxysmal and usually recurrent attacks of precordial chest discomfort (constricting, squeezing) caused by transient (15secs to 15mins) myocardial ischaemia that falls short to induce cellular necrosis.

Question 9

What is another term for ‘crescendo angina’?

Answer 9

Unstable angina

Question 10

Describe Prinzmetal angina

Answer 10

Angina due to transient spasm of artery with severe atheromatosis.

Question 11

What are the 2 types of NSTEMI?

Answer 11

ST depression and T inversion

Question 12

What is the difference between NSTEMI and STEMI in terms of their causes?

Answer 12

In NSTEMI, there is incomplete or transient occlusion.

In STEMI, there is complete and sustained occlusion.

Question 13

How is unstable angina different from other NSTEMI?

Answer 13

There are no elevated biomarkers of myocardial necrosis in unstable angina.
But in NSTEMI, there is elevated biomarkers of myocardial necrosis.

Question 14

What are the 2 types of MI and which is a more common one?

Answer 14

Subendocardial MI and Transmural MI.

Transmural MI is the more common one.

Question 15

What is dissecting aneurysm?

Answer 15

Dissecting aneurysm is an initial tear that develops in the vessel, allowing blood to track into the media.

Question 16

What are the presentations of right-sided heart failure?

Answer 16

Peripheral oedema, hepatic congestion and raised JVP.

Question 17

What does “Nutmeg appearance” indicate?

Answer 17

Hepatic congestion (and Right sided Heart Failure)

Question 18

What is Charcot Bouchard aneurysms?

Answer 18

Capillary Microanuerysm

Question 19

What type of infection can lead to mycotic aneurysm?

Answer 19

Bacterial or fungal infection.

Question 20

What is the difference between focal ischaemia and global ischaemia?

Answer 20

Focal ischaemia - part of the brain’s blood supply is disrupted. Focal complete tissue necrosis possible, depending on time.

Global ischaemia - total stoppage of blood perfusion in the brain. Pan-necrosis or selective neuronal necrosis possible depending on time. (selective neuronal necrosis is when some brain areas are more vulnerable to global ischaemia than others.)

Question 21

Lacunar infarcts are often related to which condition?

Answer 21

Small vessel disease (due to chronic hypertension) is a disease that arise when the walls of the small arteries are damaged, resulting in signs such as angina.

Question 22

What does 1 pack year means (smoking history)?

Answer 22

Smoking 20 per day for 1 year

Question 23

What are the three features of a “typical angina pain”?

Answer 23

1. Constricting discomfort on the chest, arms, shoulder, or jaw
2. Caused with physical exertion
3. Relieved with rest or GTN spray within 5mins

Question 24

What are the features of pericarditis?

Answer 24

Sharp, stabbing central chest pain. Worse on lying flat and relieved by sitting forward

Question 25

What are the features of aortic dissection?

Answer 25

Sudden severe tearing pain in the chest or between shoulder blades.
Unlike MI, it is most severe at its onset.
Note for unequal blood pressure/pulses between arms

Question 26

What are the 4 stages of lower limb ischaemia?

Answer 26

I: Asymptomatic
II: Intermittent claudication
III: Night/rest pain
IV: Tissue loss, such as ulceration or gangrene

Question 27

What is intermittent claudication most suggestive of?

Answer 27

PAD peripheral arterial disease

Question 28

High sensitivity troponin levels will start to rise how many hours after an infarction/MI?

Answer 28

3 - 4 hours later

Question 29

How long does troponin levels remain in the system?

Answer 29

2 weeks

Question 30

What are the ECG findings within hours of transmural infarction?
How about after hours or days later?

Answer 30

Hyperacute (tall) T waves, ST elevation, new LBBB.
All these occur within a few hours of transmural infarction.
After hours or days later, pathological Q waves and T wave inversion may occur.

Question 31

Where is the ST elevation/depression in the following cases of MI?

1. Anterior MI
2. Septal MI
3. Antero-lateral MI
4. Posterior MI

Answer 31

1. Anterior MI - ST elevation in V2-V4/5
2. Septal MI - ST elevation in V1 and V2
3. Antero-lateral MI - ST elevation in V1-V6, I and aVL
4. Posterior MI - ST depression in V1 - V3 and positive R wave in V1

Question 32

Which has a poorer prognosis - Anterior MI or Posterior MI or Antero-lateral MI?

Answer 32

Anterior MI

Question 33

Majority of inferior STEMI is due to blockage of which artery?

Answer 33

Right Coronary artery