Ischaemic Heart Disease

Question 1

Briefly define ischaemic heart disease?

Answer 1

When coronary aa flow does not meet demand causing ischaemia. Aka stable angina or ACS.

Question 2

What are the risk factors for developing IHD and which of these are modifiable?

Answer 2

Male
FH

Modifiable:
Smoking
Hypercholestrolaemia
Hypertension
Diabetes
Obesity and sedentary lifestyle

Question 3

How would you diagnose stable angina?

Answer 3

On the history classical central crushing chest pain on exertion which gets better with rest.

On ECG there may be ST segment depression.

May be able to see the stenosis on coronary aa angiography.

Question 4

How do you manage angina? (generally do not give the drug regimen)

Answer 4

Lifestyle advice:
Smoking cessation
Diet and Increased exercise
Control of diabetes

Pharmaceutical

Surgical:
Coronary aa bypass graft
Angioplasty with stenting

Question 5

Describe how nitrates help give symptomatic relief for angina?

Answer 5

Nitrates e.g GTN spray

Nitric oxide causes:
Venodilatation, leading to a decrease in preload and a reduction in cardiac work
Coronary vasodilatation, improves coronary blood flow

Question 6

Describe how b-blockers are helpful in treating IHD?

Answer 6

Negative ianotropic and chontropic (reduces HR) therefore reduces cardiac work.

Also coronary aa flow only occurs during diastole therefore by slowing the HR it increases the time for coronary aa flow.

Also has anti-arryhtmic properties reducing the risk of embolus formation

Question 7

Describe how Ca channel blockers are useful in treating IHD?

Answer 7

Vasodilatation improving coronary blood flow, so preventing symptoms.

Verapamil (and to a lesser extent diltiazem) also have myocardial depressant and bradycardic actions, so reducing cardiac work and increasing diastolic time.

Verapamil also exerts Class IV anti-arrhythmic activity.

Question 8

How do potassium channel activators work in IHD and give an example of a drug?

Answer 8

Nicorandil

Activates ATP sensitive K+ channels causing vasodilation of coronary aa.

Question 9

Describe the use of antiplatelet drugs in IHD?

How do they work?

Answer 9

Clopidogrel and Asprin

Reduce the risk of thrombus formation and therefore extend life.

Low dose aspirin
Favours prostacyclin production over thromboxane as it irreversibly inhibits both endothelial and platelet cyclo-oxygenase (COX). Endothelial cell are nucleated and therefore can regenerate COX, platelets lack nuclei and can not

Clopidogrel
ADP (adenosine diphosphate) receptor antagonist.
Equally efficacious used in asthmatics who cannot take aspirin.

Question 10

Describe the pharmaceutical regimen for a patient with IHD?

Answer 10

For symptomatic relief:
GTN spray

Assess CVD risk:
Statin
Low dose aspirin/clopidogrel
BP meds if hypertensive

Prevention:
1st line Beta blocker
+/- nitrates

If refractory add Ca channel blocker (not rate limiting)

Note if a beta blocker is contraindicated use a rate limiting Ca channel blocker in its place.