Myocardial Infarction

Question 1

What characterises chronic stable angina?

Answer 1

Fixed stenosis
Demand led ischaemia
Predictable
Safe

Question 2

What advice can be given when pain arises from angina?

Answer 2

Stop
Sit
Spray GTN

Question 3

What is ACS?

Answer 3

Any acute presentation of coronary artery disease:
Unstable angina
Acute NSTEMI
STEMI

Question 4

What are the stages to atherosclerosis?

Answer 4

Normal
Fatty streak
Atherosclerotic plaque
Fibrous plaque
Plaque rupture and thrombosis

Question 5

What are the characteristics of ACS?

Answer 5

Dynamic stenosis
Supply led ischaemia
Unpredictable
Dangerous

Question 6

What are factors that affect plaque rupture?

Answer 6

Lipid content of plaque
Thickness of fibrous cap
Sudden changes in intraluminal pressure or tone
Bending and twisting of an artery during each heart contraction
Plaque shape
Mechanical injury

Question 7

What history is indicative of an MI?

Answer 7

Severe crushing central chest pain
Radiating to jaw and arms, especially the left
Similar to angina but more severe, prolonged and not relieved by GTN
Associated with nausea, sweating and vomiting

Question 8

What ECG changes can be seen in an acute STEMI?

Answer 8

ST elevation - more than 1mm in 2 adjacent limb leads or more than 2mm in at lead 2 contigous precordial leads
New onset BBB
T wave inversion
Q waves

Question 9

Where is ST elevation seen in an inferior MI?

Answer 9

Leads 1, 2 and aVF

Question 10

Where is ST elevation seen in an anteroseptal MI?

Answer 10

V1-4

Question 11

Where is ST elevation seen in an anterolateral MI?

Answer 11

1, aVL, V1-6

Question 12

How is a MI diagnosed by cardiac enzymes?

Answer 12

CK (peaks in 24 hours but nonspecific)

Tn (troponin which is highly specific for cardiac muscle damage)

Question 13

What anti-platelets should patients with an MI be given?

Answer 13

Aspirin and clopidogrel

Question 14

What are the indicataions for reperfusion therapy (thrombolysis or PCI)?

Answer 14

Chest pain suggestive of MI (more than 20 mins but less than 12 hours)
ECG changes (acute ST elevation or new LBBB)
No contraindications

Question 15

What are the risks to thrombolytic therapy?

Answer 15

Failure to re-perfuse
Haemorrhage (minor, major or intercranial)
Hypersensitivity

Question 16

What is given in the early treatment of a STEMI?

Answer 16

Analgesia - diamorphine
Antiemetic 
Aspirin and clopidogrel 
GTN if BP is over 90 systolic 
Oxygen if hypoxic
Primary angioplasty 
Thrombolysis if angioplasty is not avaliable within 90 mins

Question 17

What are complications of an acute MI?

Answer 17

Death
Arrhythmic complications
Structural complications
Functional complications

Question 18

What are the arrhythmic complications associated with an acute MI?

Answer 18

Ventricular fibrillation (V-Fib)

Question 19

What are the structural complications associated with an acute MI?

Answer 19

Cardiac rupture
Ventricular septal defect 
Mitral valve regurgitation 
Left ventricular aneurysm formation 
Mural thrombus
Inflammation 
Acute pericarditis
Dressler's syndrome

Question 20

What are the functional complications associated with an acute MI?

Answer 20

Acute ventricular failure (left, right or both)
Chronic cardiac failure
Cardiogenic shock

Question 21

What does troponin mark?

Answer 21

Emoblization, microvascualr circulation and myonecrosis

Preferably biomarkers TnT or Tnl

Question 22

What other conditions can cause an elevated TnT?

Answer 22

CCF
Hypertensive crisis
Renal failure
PE
Sepsis
Stroke/TIA
Pericarditis
Post arrythmia

Question 23

What are the targets post-MI?

Answer 23

Avoid smoking
Healthy diet
Regular aerobic exercise
Optimal drug therapy 
Cholesterol <4.0 mmol/l
BP <140/85 mmHg 
Diabetes, renal disease, target organ damage <130/80 mmHg

Question 24

What receptor is expressed that allows for platelet aggregation?

Answer 24

GP 2b-3a which fibrinogen will bind to