MI

Question 1

What are the characteristics of an MI

• site, radiation
• character
• triggers
• relief
• duration

Answer 1

Site, radiation
-diffuse, ant chest, l arm, neck

Character
-tight, pressure, dull, weight

Triggers

• physical, emotional stress
• cold

Relief
-rest, GTN

Duration

• <30mins => angina
• > 30mins => MI

Question 2

Why do we get pain in MIs

Answer 2

Stenosis > 80% => ischemia as demand > supply

Increase in metabolites (bradykinin, adenosine) => visceral pain

Question 3

Why do we get breathless in MIs

Answer 3

Decreased CO => increased LVEDP => net mv of fluid into lungs => decreased gas exchange

Question 4

How would you diagnose an MI

• ECG
• Troponin

Answer 4

ECG
-ST elevation or no ST elevation

Troponin
-significantly increased

Question 5

What are the 2 types of MI

Answer 5

STEMI
-transmural, complete occlusion

NSTEMI
-subendocardial, partial occlusion

Question 6

How does atherosclerotic plaque rupture lead to MI

Answer 6

Foam cells induce SM death => protease release
=> soften collagen in cap

Platelets gather at rupture side => thrombus => stenosis

Question 7

How would you treat the thrombus

• drugs
• mechanical

Answer 7

Drugs

• statins
• antiplatelets
• anticoagulants

Mechanical
-PCI => increase perfusion, decrease stroke and bleed risk

Question 8

How would you treat the decreased coronary flow

Why would you use these drugs

Answer 8

Antianginals

• B blockers
• L type Ca blockers
• nitrates

Decrease the cardiac load and strain
Increase the amount of coronary perfusion

Question 9

How would you prevent future MIs
-2 methods
What drugs would you use

Answer 9

Reduce effect of stenosis

• Statins
• ACEi
• B block
• Aspirin
• ADP inh

Reduce wall stress from dilation

• ACEi
• B block
• MC RAs