Ischaemic heart disease: acute coronary syndrome (ACS)

Question 1

What makes up ACS

Answer 1

1. ) Unstable angina
2. ) Non ST-elevation MI (NSTEMI)
3. ) ST-elevation MI (STEMI)

Question 2

Describe the aetiology of ACS

Answer 2

• Through a thrombosis from a ruptured atherosclerotic plaque

Question 3

Describe the pathophysiology of ACS

Answer 3

• ACS occurs when an atherosclerotic plaque ruptures, resulting in a thrombosis. This will lead to ischaemia of the heart.
• In unstable angina: ischaemia is experienced but not infarction as here the plaque has not yet ruptured
• In a NSTEMI: ischaemia takes place as well as distal infarction
• In a STEMI: ischemia takes place alongside initial distal infarction that moves proximally (a transmural infarction). Coagulative necrosis of cardiac myocytes takes place and this leads to oedema. This leads to neutrophils infiltrating the site and they will undergo necrosis. Lastly macrophages will enter to ‘clean’ up the area and fibroblasts deposit collagen, forming scarred tissue

Question 4

What are the clinical signs of ACS

Answer 4

• Chest pain that is exacerbated by cold weather/anger/exciement

Question 5

What are the symptoms of ACS

Answer 5

• Central crushing retrosternal pain that radiates to the jaw and arm
• Dyspnoea
• Excess sweating
• Shortness of breath
• Nausea/vomiting
• Impending sense of doom

Question 6

Describe the investigations for ACS

Answer 6

1. ) Coronary angiography
2. ) 12 lead ECG:
   - Unstable angina: normal, may show T wave inversion
   - STEMI: shows ST elevation and later on a pathological Q wave
   - NSTEMI: Shows ST depression
3. ) Cardiac enzyme testing:
   - Troponin
   - CK-MB
   - When cardiac myocytes undergo necrosis, they release CK-MB and troponin into the blood. These levels are high in the first 2 days of an MI
   - Good for diagnosis of an MI (NSTEMI/STEMI show but unstable angina does not)
4. ) STEMI: NEW LBBB (William)
   - look at left leads V1 and V6
   - V1: has a ‘W’ QRS inversion shape
   - V6 has an ‘M’ shaped QRS wave
5. ) FBC: anaemia
6. ) Glucose/lipid profile/U&E’s

Question 7

Describe the management options for ACS

Answer 7

Initial management for any ACS patient: MOAN

• M: morphine (IV opioids)
• O: oxygen (if O2 saturation is >93%)
• A: Aspirin + clopidogrel (a antiplatelet medication to thin blood)
• N: Nitrates (pain relief)

Once this is done: move onto meds/surgery/lifestyle

1. ) Surgical:
   - STEMI: first line is a PCI (percutaneous coronary intervention)
   - If this is not available/person has presented too late, then fibrinolytic therapy (thrombolysis) is chosen: this aims to remove the thrombus that is blocking the coronary artery. Alteplase is used for this

2.) Pharmacological (for all ACS patients): ABAS

• A: Ace inhibitors/angiotensin receptor antagonist
• B: beta blocker
• A: aspirin + clopidogrel
• S: Statins

3. ) Lifestyle adaptations
   - Quit smoking
   - Healthier diet
   - Regular exercise

Question 8

Describe some of the differential diagnosis for ACS

Answer 8

• Pericarditis (inflammation of the pericardium that surrounds the heart)
• Endocarditis (inflammation of the endocardium, the hearts inner lining)
• Aortic Aneurysm (swelling in the abdominal aorta that could rupture)
• Pericardial effusion tamponade (severe compression of the heart due to the rapid accumulation of fluid)
• Oesophageal rupture
• Pulmonary embolism (is a blockage in one of the pulmonary arteries in your lungs)
• Anxiety

Question 9

Describe the non-modifiable risk factors for ACS

Answer 9

1. ) Family history
2. ) Male sex
3. ) Increasing age

Question 10

Describe the modifiable risk factors for ACS

Answer 10

1. ) Sedentary lifestyle
2. ) Poor diet
3. ) Obesity
4. ) Smoking
5. ) Hypertension
6. ) Dyslipidaemia

Question 11

Describe some of the complications of ACS

Answer 11

Early complications include:

• Arrhythmias:
  1. ) Tachycardia: sinus/VF/AFib
  2. ) Bradycardia: Sinus/AV block

Question 12

Describe the anatomy of the coronary arteries and where each bit supplies (extra to help understanding)

Answer 12

• From the aorta you get two coronary arteries: the right and left coronary arteries
• Left coronary artery: forms the LAD (left anterior descending) and the left circumflex.
• LAD supplies the anterior portion of the heart
• Left circumflex supplies the lateral portion of the heart
• Right coronary artery wraps around from anterior to posterior