Ischaemic Heart Disease

Question 1

Pathophysiology of STEMI

Answer 1

TRANSMURAL INFARCT (commonest) – the ischaemic necrosis involves the full or nearly full thickness of the ventricular wall in the distribution of a single coronary artery. Usually associated with coronary atherosclerosis, plaque rupture and super-imposed thrombosis.

Question 2

Pathophysiology of NSTEMI and unstable angina

Answer 2

SUBENDOCARDIAL INFARCT –
ischaemic limited to the inner one-third, or at most one-half, of the ventricular wall. There is diffuse stenosis secondary to coronary atherosclerosis and global reduction of coronary flow (e.g. due to shock) but no plaque rupture and no thrombosis.

Question 3

Advantages of Troponin assays

Answer 3

sensitive to low levels

within 3 hours

Question 4

Cardiac causes of raised troponin levels?

Answer 4

ACS

Fast AF

Need to look at whole picture

Question 5

High sensitivity troponin

Answer 5

Strong –ve predictive value

If no dynamic change, then unlikely to have had MI event so can discharge and treat as OPD (angioi/echo)

Question 6

Non- cardiac causes of troponin

Answer 6

Cerebrovascular events
SAH
Endocrine disease
Polymyositis, dermatomyositis
Renal disease (53% in ESRD)– renally excreted
Haematological malignancies
Septic patients
Pulmonary embolic disease

Question 7

Describe a ACS Risk Model

Answer 7

GRACE

Question 8

What does ST Elevation on ECG mean

Answer 8

marker of complete coronary occlusion

Question 9

What does ST Depression on ECG mean

Answer 9

Incomplete occlusion

Question 10

Other causes of ST- elevation

Answer 10

Acute pericarditis
Myocarditis
Massive PE (VI-V2 occasionally)
Brugada-type patterns (V1-V3 with RBBB morphology)
Hyperkalaemia (V1-V2)
Hypothermia
Hypercalcaemia

Question 11

GPIIb/IIIa inhibitors in ACS

Answer 11

potent intravenous antiplatelet drugs