Acute Coronary Syndromes

Question 1

Describe the common symptoms of ischaemic chest pain

Answer 1

Usually central

Radiation (not always present) to inner left arm, (also sometimes abdomen, neck)

Crushing, band-like, heavy

Duration: remits with rest if exerton related

Exacerbating factors: exercise, stress, tachycardia

Relieving factors: rest, GTN

Question 2

What features may be seen on examination in a patient with ischaemic chest pain?

Answer 2

If symptoms have settled, examination often normal.

Can exhibit:

• Pallor
• Hypotension
• Tachycardia
• Diaphoresis
• Cold/clammy skin
• Central or peripheral cyanosis, low SpO₂
• Bibasal crackles (left ventricular failure)
• Raised JVP (right ventricular failure)
• Hepatomegaly (right ventricular)
• Pedal lower limb and sacral oedema (right ventricular failure)
• Mitration regurgitation (3rd and 4th heart sounds) (damage to papillary muscles)

Question 3

What are the main differences between unstable angina, NSTEMI and STEMI?

Answer 3

Unstable Angina:

• Clinical entity (no pathological damage to cardiac muscle)
• Pain at rest or with minimal exertion
• No major ECG changes, changes may be non-specific
• Troponin normal
• No infarction, does not involve necrosis

NSTEMI:

• Clino-pathological entity
• Ischaemic damage to cardiac muscle, subendocardial not transmural
  
  • ECG changes often show ST depression ⁺/- T-wave inversion
  • ECG changes may be non-specific
• History may be similar to UA
• Troponin rises then falls

STEMI:

• Infarction and necrosis of cardiac muscle, often transmural
• Persistent ST-elevation on ECG
• Troponin raised
• Symptoms more severe than NSTEMI or UA

Question 4

What potential consequences are associated with acute coronary syndromes?

Answer 4

• Hypotension
• Cardiogenic shock
• AKI
• Tachyarrhythmias
• Bradyarrhythmias
• Conduction defects
• Pericarditis
• Ventricular aneurysm
• Cardiac rupture
• Mural thrombosis
• Post MI (Dressler’s) syndrome

Question 5

What else can cause a raised troponin?

Answer 5

Renal failure

In the absence of other causes however it is highly specific and sensitive to ischaemic myocardial damage.

Question 6

Describe the phases of acute MI

Answer 6

Ischaemic phase (acute phase):

• Myocardium survives on anaerobic metabolism initially

Infarction phase:

• Anaerobic metabolism cannot keep up with metabolic demand- irreversible damage and cell death occur

Question 7

What are pathological Q waves associated with?

Answer 7

Infarction

• NSTEMI or STEMI

Question 8

What would ST elevation in V1-V6 indicate?

Answer 8

V1-V2: Septal

V3-V4: Anterior/septal

V5-V6: Lateral

(V1-V4 extensive anterior)

Question 9

What is used in primary and secondary prevention of ACS?

Answer 9

Statins

B-blockers

ACE-Inhibitors

Aspirin/Clopidogrel

Smoking cessation

Diet

Exercise

Question 10

What is used in the treatment of ACS?

Answer 10

• Oxygen
• Aspirin/clopidogrel
• LMWH
• Opiates
• Nitrates
• Thrombolytics
• B-blockers
• PCI
• CABG

Question 11

What is used to treat the complications associated with ACS?

Answer 11

• Anti-arrhythmics
• Percutaneous, temporary and permanent pacemakers,
• Ionotropes
• Diuretics
• Intra-aortic balloon pump
• Adrenalin
• Atropine