IHD Flashcards
Name the areas supplied by the coronary arteries?
LAD supplies anterior wall and ant 2/3 of septum
LCX supplies lateral surface
PD supplies post wall and past 1/3
What are the factors affecting myocardial oxygen supply?
- Perfusion pressure - systemic hypotension
- Coronary vascular resistance - Coronary artery atherosclerosis
- External compression - due to myocardial contraction
- Intrinsic regulation (endothelium and local metabolites)
What is the difference between stable and unstable angina?
Stable Angina: reproducible cardiac chest pain that occurs on exertion and goes away with rest
- Due to atherosclerotic narrowing of a vessel
- Endothelial dysfunction
Symptoms generally start at 70% stenosis
Unstable Angina: Presents as cardiac chest pain that may occur at rest or minimal exertion and may not resolve with rest
- Acute plaque event
- Coronary artery thrombosis
- Resolves
- No irreversible damage
What is the difference between a Non- transmural and transmural infarct?
Non- transmural: transient/ partial obstruction, regional sub-endocardial infarct
Transmural: complete obstruction, full thickness endocardial infarct
What is the pathogenesis of chronic myocardial ischaemia and how does it differ from MI?
With chronic atherosclerotic narrowing of vessels:
- Small areas of sub-endothelial ischaemia
- Patchy myocyte necrosis and replacement by fibrosis
- carries risk of cardiac failure and arrhythmia
i.e. patchy not confluent area of infarction
What is the cause of Sudden Cardiac Death?
majority due to IHD: frequently an early arrhythmic event, but can also be a catastrophic mechanical complication of a “silent” MI within the last few days
What are other causes of MI?
Other Vascular Pathology (Non Atherosclerosis)
- Coronary Artery Dissection
- Thrombosis due to Vasculitis
- Thromboembolism from the heart
Reduced Flow / Oxygenation
- Hypotension (Shock)
- Rapid Tachycardia
- Hypoxaemia
