Acute Coronary Syndromes

Question 1

What is the outcome of blood vessel narrowing

Answer 1

Inadequate oxygen delivery for tissue needs
Ischaemia in infected tissue
If persisting irritation and damage, specialised tissue becomes fibrotic

Question 2

What is the outcome of blood vessel occlusion

Answer 2

No oxygen delivery causing more severe pain and tissue death and loss of function

Question 3

What are the main arteries supplying blood to the heart and where do they come from

Answer 3

Right coronary artery
Left anterior descending artery
Circumflex coronary artery
Come from the root of aorta

Question 4

At which HRs are cardiac problems most often found

Answer 4

Fast HRs because as HR increases, the time period for diastole reduces, compromising cardiac blood flow

Question 5

When are coronary arteries tested

Answer 5

During exercise or at high HR

Question 6

Where does atherosclerosis happen

Answer 6

At areas of stress to the artery and where there is turbulent blood flow

Question 7

What happens in atherosclerosis

Answer 7

The change in blood flow causes damage to the interior surface of the artery and allows accumulation of fat within the surface which forms the atherosclerotic plaque
These gradually increase in size and narrow the vessel, reducing blood flow

Question 8

Describe atherosclerosis as an acute coronary syndrome

Answer 8

Atherosclerosis attracts platelets to the vessel which will attract clotting factors and eventually cause occlusion of the vessel

Question 9

What is spasm of the artery and how is it often termed

Answer 9

Muscle within vessel walls can contract causing narrowing of the artery often termed Prinzmetal’s angina

Question 10

Describe the line between reversible and irreversible ischaemia

Answer 10

Reversible if less that 20 minutes occlusion, if occlusion takes longer than 20 minutes to clear, there will be permanent cardiac muscle damage

Question 11

What are the different acute coronary syndromes

Answer 11

Stable angina
Unstable angina
STEMI
NSTEMI

Question 12

Describe stable angina

Answer 12

Atherosclerosis restricts blood flow
If oxygen requirements beyond the plaque is higher than the tissue can deliver, the patient can have anaerobic metabolism and eventually lactic acidosis in the tissue, causing angina pain

Question 13

When can stable angina be reversed

Answer 13

Reversible if oxygen requirements are reduced - can be done by stopping the exercise or increasing blood flow through the area

Question 14

Describe the ECG of stable angina

Answer 14

Normal ECG

Question 15

Describe the troponin levels for stable angina

Answer 15

Troponin stable as there is little cardiac death

Question 16

Describe unstable angina

Answer 16

Patient can develop pain at any time because build up of plaque remains stable but clot on surface doesn’t extend to occlude the lumen
The clot will gradually be removed by the body and the lumen will open again
Isn’t associated with exercise so can be very difficult to differentiate from MI

Question 17

Describe the ECG of unstable angina

Answer 17

Depression of the ST segments and inversion of the T waves

Question 18

Describe the troponin levels for unstable angina

Answer 18

Stable as there is little cardiac death

Question 19

Describe a STEMI

Answer 19

Often transmural changes - thickness of cardiac muscle wall changes
Atherosclerosis has developed a clot which has increased to occlude the vessel completely so no blood or oxygen can pass to the tissues

Question 20

Describe an NSTEMI

Answer 20

No ST elevation, may be depression

Associated with a sub-endo cardiac infarct - interior layer of care disc muscle is infected

Question 21

What cardiac biomarkers exist

Answer 21

Myoglobin
CK-MB
Troponin

Question 22

Rank the cardiac biomarkers in effectiveness

Answer 22

Myoglobin is less effective

CK-MB used to be the preferred test but troponin is much more specific and easier to access

Question 23

When should troponin be tested and why

Answer 23

Patient needs test done when they arrive at the hospital and 24 hours later
If raised troponin at time of admission, it is clear the patient has an MI
Troponin will have a peak between 24-48 hours