Cardiovascular Diseases 5

Question 1

ISCHAEMIA can be defined as an imbalance between _________ and ________.

Answer 1

the supply (perfusion), the demand of the heart for oxygenated blood

Question 2

> 90% ischemia cases are caused by ____________.

Answer 2

atherosclerosis of the coronary arteries

Question 3

Ischemia can manifest itself in 4 different ways in the heart. What are they?

Answer 3

1. Myocardial Infarction
2. Angina
3. Chronic Ischaemic Heart Disease
4. Sudden cardiac death

Question 4

What is the difference between ISCHAEMIA, INFARCTION + REPERFUSION?

What are 4 cardiovascular causes for ischemia?
What are 2 cardiovascular causes for infarction?

Answer 4

Isch: inadequate blood supply to an organ
Infar: myocardial cell death caused by longer blockage of blood supply (lack of oxygen)
Reper: restoration of blood flow, hopefully before necrosis sets in

ISCHAEMIA

1. Irregular heart beat (tachycardia)
2. Atherosclerosis
3. Hypertrophy of the heart
4. Thromboembolism (blood clot)

INFARCTION

1. Atherosclerotic plaque ruptures —> thrombus formation —> embolism
2. Heart muscle dies and cannot be regenerated

Question 5

Difference between a MURAL and OCCLUSIVE thrombus?

Answer 5

T: a partial obstruction of the vessel - prone to embolise
O: blocks the entire artery - nothing is being perfused

Question 6

Difference between a TRANSMURAL and SUB-ENDOCARDIAL thrombus?

Answer 6

T: necrosis of the near-to-full thickness of the ventricular wall in the distribution of a single coronary artery
S: necrosis limited to inner (furthest) 1/3-1/2 of the ventricular wall (the sub-endocardial region) where the least perfusion exists

Question 7

What are 3 facts regarding the biochemical mechanisms during ischeamia?

Answer 7

1. Aerobic glycolysis ceases and anaerobic glycolysis kicks in - ATP decreases, lactic acid increases
2. Poor contractility of muscles (due to decreased ATP and increased lactic acid)
3. Reperfusion within 20-40mins can prevent cell death. After this, necrosis occurs.

Question 8

What are 2 examples of REPERFUSION INJURIES?
Are these injuries permanent? Why/why not?

What 5 types of cells are affected?

Answer 8

1. Production of lots of ROS from incoming leukocytes
2. Calcium overload

Not permanent - myocardial shocking. New cells generate over time.

Troponin I
Troponin T
Myosin Light Chain 2
Creatine Kinase
C-Reactive Protein

Question 9

Lots of people die from MI, but for those that recover what 4 complications can occur?

Answer 9

1. Chronic contractile dysfunction
2. Arrhythmias
3. Myocardial rupture (in the area of necrosis since this tissue is weak)
4. Ventricular aneurysm (the area where scarring has occurred is weak)