Acute Coronary Syndrome

Question 1

Acute coronary syndrome

It covers a number of presentations, including

• ST elevation myocardial infarction (STEMI)
• non-ST elevation myocardial infarction (NSTEMI)
• unstable angina

Answer 1

ACS generally develops in patients who have ischaemic heart disease due to the gradual build up of fatty plaques:

1. Gradual narrowing, resulting in less blood and therefore oxygen reaching the myocardium at times of increased demand. This results in angina, i.e. chest pain due to insufficient oxygen reaching the myocardium during exertion
2. The risk of sudden plaque rupture. The fatty plaques which have built up in the endothelium may rupture leading to sudden occlusion of the artery. This can result in no blood/oxygen reaching the area of myocardium.

Question 2

Acute coronary syndrome

Pathophysiology

Answer 2

Signs and symptoms

Question 3

Acute coronary syndrome

ECG Changes (1)

ECG showing a ST elevation myocardial infarction (STEMI). Note by how looking at which leads are affected (in this case II, III and aVF) we are able to tell which coronary arteries are blocked (the right coronary artery in this case). A blockage of the left anterior descending (LAD) artery would cause elevation of V1-V4, what is often termed an ‘anterior’ myocardial infarction.

Answer 3

• ECG showing a non-ST elevation myocardial infarction (NSTEMI). On the ECG there is deep ST depression in I-III, aVF, and V3-V6. aVR also has ST elevation.
• Deep and widespread ST depression is associated with very high mortality because it signifies severe ischemia usually of LAD or left main stem.

Question 4

Acute coronary syndrome

ECG Changes (2)

The table below shows a simplified correlation between ECG changes and coronary territories:

Answer 4

Diagram showing the correlation between ECG changes and coronary territories in acute coronary syndrome:

Question 5

Acute coronary syndrome

Management

Answer 5

Secondary prevention: