Infarction and Ischaemia

Question 1

What is ischaemia?

Answer 1

Inadequate supply of blood to a tissue resulting in insufficient supply of oxygen
It is reversible

Question 2

What is infarction?

Answer 2

Cell / tissue death

Question 3

What causes infarction?

Answer 3

Ischaemia

Question 4

What are modifiable risk factors of ischaemia?

Answer 4

Unhealthy diet
Unhealthy blood cholesterol
Sedentary lifestyle
Hypertension
Smoking
Alcohol
Stress

Question 5

What are non-modifiable risk factors of ischaemia?

Answer 5

Age
Family history
Ethnicity
Diabetes*

Question 6

What is the leading cause of ischaemic heart disease?

Answer 6

Atheroma / thrombosis

Question 7

What happens in ischaemia heart disease?

Answer 7

Hypoxia of cardiac myocytes –> reduced generation of ATP –> reduced ventricular systolic contraction and diastolic relaxation

Question 8

What happens to cells in ischaemic heart disease?

Answer 8

Changes to cell structure (mitochondrial swelling within minutes)
Irreversible cell death (20-40 mins after onset)

Question 9

What happens if repercussion occurs?

Answer 9

There is an area of stunned myocardium

If the area is small it could persist for hours-days but the contractile function gradually recovers

If the area is large, you may not be able to sustain life or you will require supportive care until myocardium regains function

Question 10

What is stable angina, what is it caused by, what can it be relieved by and where can the pain radiate to?

Answer 10

Symptomatic paroxysmal chest pain
Caused by myocardial ischaemia
Precipitated by physical exertion, exposure to cold, emotional stress
Relieved within mins by rest or GTN
Pain can radiate to arms or jaw

Question 11

What is variant angina, what is the pain and how can it be relieved?

Answer 11

Angina occurring at rest
Coronary artery spasm
Occurs without any underlying coronary artery condition
Can be relieved by medication

Question 12

What is silent angina?

Answer 12

Angina but without experiencing any anginal pain

Question 13

What is unstable angina, how does it occur and can it be relieved?

Answer 13

Angina occurring at rest
Occurs suddenly and worsens over time
Cannot be relieved by medication

Question 14

What is a STEMI, describe the pain, how can it be relieved and how do patients appear with it?

Answer 14

Central precordial chest pain
Described as a more severe angina type pain
Often radiates to arms and/or jaw
Can be relieved by opiate analgesia
Patients appear syncopal, pale, clammy and SOB

Question 15

Diagnosing an MI

Answer 15

Troponin-T rise
ECG changes suggestive of ischaemia

Question 16

What is an NSTEMI, how can it look on an ECG, how can it be seen from troponin-T, how will the patient appear and how can it be treated?

Answer 16

Less severe form of a STEMI
ST depression and/or T wave depression
Raised troponin-T
Patients appear pale, clammy, looking unwell, may be clutching at chest
Need to treat with morphine

Question 17

Acute management of Acute Coronary Syndrome

Answer 17

Morphine
Oxygen
Nitrates
Aspirin
Clopidogrel

Question 18

What to do post MI?

Answer 18

Echocardiography
- see how the infarction has affected the contraction ability of the heart

Coronary angiography
- inject dye into coronary arteries and take images of arteries using x-rays
- allows for immediate intervention (stenting)