Myocardial Infarction

Question 1

What is MI?

Answer 1

Occurs when there is Myocardial necrosis following atherosclerotic plaque rupture, which occludes one or more of the coronary arteries.

Question 2

What is the cause of an MI?

Answer 2

Atherosclerosis

Question 3

What are the symptoms of MI?

Answer 3

1. Nausea, sweating, palpitations
2. Crushing chest pain for more than 20 mins
3. NB. Can be silent in diabetics

Question 4

What are the signs for MI?

Answer 4

Remember RIP:
R - raised JVP
I - increased pulse, BP changes
P- pallor, anxiety

Question 5

What are the 2 different types of infarct?

Answer 5

1. Transmural

2. Subendocardial

Question 6

Discuss the features of a transmural infarct?

Answer 6

• Affects all of the myocardial wall

- ST elevation and Q waves

Question 7

Discuss the features of a subendocardial infarct?

Answer 7

• Necrosis of <50% of the myocardial wall

- ST depression

Question 8

What investigations would you do if you suspected an MI?

Answer 8

ECG, CXR, Bloods.

Question 9

What would the investigations show?

Answer 9

ECG:

• ST elevation, ST depression, inverted T waves
• New LBBB
• pathological Q waves

CXR:

• cardiomegaly
• Pulmonary oedema
• Widening of the mediastinum

Bloods:

• Troponin I
• Troponin T

Angiography with the view to perform percutaneous coronary intervention (PCI)

Question 10

What is the conservative

+ medical treatment of an MI?

Answer 10

Conservative: smoking cessation + increase exercise.

Medical MONA B: 
M - morphine 
O - oxygen (if hypoxic) 
N - nitrates (GTN) 
A - anticoagulants, e.g. aspirin and an antiemetic 

B - beta blockers if no contraindication

Question 11

What should all patients be prescribed on discharge?

Answer 11

aspirin, an ACEi, a beta blocker (if no CI - if so calcium channel blockers are a good alternative) and a statin

Question 12

What is the surgical treatment of MI?

Answer 12

Reperfusion with PCI if STEMI. PCI may also be used in NSTEMI but if NSTEMI patients arenot having immediate PCI, fondaparinux (a factor Xa inhibitor) or a low molecular weight heparin (LMWH) may be given subcutaneously

Question 13

What are the complications of MI?

Answer 13

C PEAR DROP:

C- cardiogenic shock, cardiac arrhythmia

P - pericarditis
E - emboli
A - Aneurysm formation
R - rupture of ventricle

D - Dressler’s syndrome
R - rupture of the free wall
O -
P - papillary muscle rupture

Question 14

How does AF present?

Answer 14

irregularly irregular pulse, absent P waves, irregular RR intervals, an undulating baseline and narrow complex QRS.

Question 15

What is Dressler’s syndrome?

Answer 15

An autoimmune pericarditis that develops 2-10 weeks post MI. this is a triad of:

1. fever
2. pleuritic pain
3. pericardial effusion