Ischaemia refers to a lack of oxygen due to inadequate perfusion of the myocardium, which is due to an imbalance between oxygen supply and demand. The spectrum of coronary artery disease ranges from stable coronary artery disease, asymptomatic coronary artery disease, unstable angina, acute myocardial infarction, ischaemic cardiomyopathy and sudden cardiac death.
The causes are as follows:
1)Coronary blood flow to a region of the myocardium may be reduced by a mechanical obstruction that is due to: (The first two are the most frequent).
• Atheroma
• Thrombosis
• Spasm
• Embolus
• Coronary ostial stenosis
• Coronary arteritis (e.g. in SLE).
2)There can be a decrease in the flow of oxygenated blood to the myocardium that is due to:
• Carboxyhaemoglobinaemia (rare)
• Hypotension causing decreased coronary perfusion pressure.
3) An increased demand for oxygen may occur owing to an increase in cardiac output (e.g.thyrotoxicosis) or myocardial hypertrophy (e.g. from aortic stenosis or hypertension).
4) Congenital–coronary anomalies.
The causes are as follows:
1)Coronary blood flow to a region of the myocardium may be reduced by a mechanical obstruction that is due to: (The first two are the most frequent).
• Atheroma
• Thrombosis
• Spasm
• Embolus
• Coronary ostial stenosis
• Coronary arteritis (e.g. in SLE).
2)There can be a decrease in the flow of oxygenated blood to the myocardium that is due to:
• Carboxyhaemoglobinaemia (rare)
• Hypotension causing decreased coronary perfusion pressure.
3) An increased demand for oxygen may occur owing to an increase in cardiac output (e.g.thyrotoxicosis) or myocardial hypertrophy (e.g. from aortic stenosis or hypertension).
4) Congenital–coronary anomalies.
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