Acute Coronary Syndrome and Acute Myocardial Infarction Presentation and Investigation

Question 1

What is an acute coronary syndrome?

Answer 1

Any sudden cardiac even suspected or proven to be related to a problem with the coronary arteries

Question 2

What is myocardial infarction?

Answer 2

Coronary cell death due to ischaemia

Question 3

What are the causes of myocardial infarction?

Answer 3

Complete coronary artery occlusion

Partial or transient complete coronary artery occlusion

Question 4

What are the causes of MI not related to coronary atherosclerosis?

Answer 4

Coronary vasospasm
Coronary dissection
Embolism of material down a coronary artery
Inflammation of coronary arteries
Radiotherapy to the chest causing fibrosis and stenosis of coronary arteries

Question 5

What are some causes of coronary vasospasm?

Answer 5

Cocaine
Triptans
5-FU chemotherapy

Question 6

What artery is affected in an inferior MI?

Answer 6

Right coronary artery

Question 7

What artery is affected in an anterior MI?

Answer 7

Left anterior descending coronary artery

Question 8

What artery is affected in a lateral MI?

Answer 8

Circumflex coronary artery

Question 9

What can a posterior MI be easily missed?

Answer 9

As there are no ECG leads on the posterior chest

Question 10

Why are some inferior changes also seen in a posterior MI?

Answer 10

As posterior wall is usually supplied by the right coronary artery

Question 11

What is a STEMI caused by?

Answer 11

A completely occluded artery

Question 12

What does a STEMI cause?

Answer 12

Outgoing myocyte death

Question 13

What needs to be done ASAP in a STEMI?

Answer 13

Coronary artery needs to be opened with reperfusion therapy, mechanically in cath lab or pharmacologically

Question 14

What is the difference in patients affected by NSTEMI compared to STEMI?

Answer 14

Patients with NSTEMI tend to be older, more likely to have had a previous MI and are more likely to have had previous CABG or PCI

Question 15

What is the common pathogenesis of NSTEMI?

Answer 15

Atherosclerotic plaque rupture or erosion
Superimposed platelet aggregation and thrombosis
Vasospasm and vasoconstriction
Subtotal or transient total occlusion of vessel

Question 16

What are the risk factors of MI?

Answer 16

Male
Age
Known heart disease
Hypertension
Hypercholesterolaemia
Diabetes
Smoking
FH of premature heart disease

Question 17

What is the typical clinical presentation of an MI?

Answer 17

Chest pain - central crushing/heavy
May radiate to neck/arm/jaw
Often described as discomfort more than pain
May be associated with nausea, sweating and breathlessness

Question 18

What will the initial ECG of a complete coronary artery occlusion show?
What will the ECG show at 3 days?

Answer 18

ST elevation

Will show Q waves at 3 days

May also show hyper-acute T waves

Question 19

What changes will be seen on the ECG of a partial coronary artery occlusion?

Answer 19

Initial ECG will show no ST elevation and no Q waves at 3 days

May show ST segment depression or T wave inversion on the initial ECG

May be normal

Question 20

What is the difference between a STEMI Q wave MI and a NSTEMI non-Q wave MI?

Answer 20

STEMI Q wave MI is transmural

Non-Q wave MI is subendocardial

Question 21

How is an MI diagnoses?

Answer 21

Detection of cardiac cell death through positive cardiac biochemicals (troponin) and one of;
Symptoms of ischaemia
New ECG changes
Evidence of coronary problem on coronary angiogram or autopsy
Evidence of new cardiac damage on another test

Question 22

What are some non-cardiac causes of troponin rise?

Answer 22

Pulmonary embolism
Sepsis
Renal failure
Sub-arachnoid haemorrhage

Question 23

What agents are given as a bolus in thrombolysis?

Answer 23

Tenecteplase

Alteplase and streptokinase are older agents

Question 24

When is thrombolysis contraindicated?

Answer 24

Recent stroke or previous intracranial bleed

Question 25

When is caution needed in thrombolysis?

Answer 25

Recent surgery
Warfarin treatment
Severe hypertension

Question 26

What are the advantages and disadvantages of thrombolysis?

Answer 26

Works if given very early
More likely to cause bleeding problems
May not work, especially in delayed presentation

Question 27

When should patients be referred to the cath lab?

Answer 27

If they can get there within 2 hours of STEMI

Question 28

What is the general management of a suspected acute coronary syndrome?

Answer 28

Admission to hospital
Cardiac monitor
O2 if levels are low

Question 29

What investigations should be done in suspected acute coronary syndrome?

Answer 29

Serial ECGs, consider posterior leads
Blood tests
Check for anaemia
Kidney function tests
Cholesterol levels
Thyroid hormone levels

Question 30

What drugs can be given for chest pain in a suspected acute coronary syndrome?

Answer 30

GTN

Opiates

Question 31

What drugs can be used in the treatment of an acute coronary syndrome?

Answer 31

Antiplatelets e.g. aspirin
anti-thrombotic drugs e.g. heparin
Beta blockers e.g. bisoprolol
Statins e.g. simvastatin
ACEI e.g. ramipril

Question 32

What are the risks of coronary angiography/angioplasty/stenting?

Answer 32

Bleeding 
Blood vessel damage
Myocardial infarction 
Coronary perforation
Stroke
Dye can affect kidneys and cause contrast nephropathy

Question 33

What are the potential complications following MI?

Answer 33

Arrhythmia 
Cardiogenic shock 
Myocardial rupture
Valve dysfunction
Papillary muscle dysfunction or rupture
Acute ventricular septal defect