Ischaemic heart disease
- Mechanism
The heart muscle suffers when its supply of oxygenated blood falls short of demand, almost always because of coronary atherosclerosis.
What it is
Ischaemic heart disease is a group of syndromes caused by an imbalance between myocardial oxygen supply and demand. In more than nine of ten cases the cause is coronary atherosclerosis, through fixed stenosis, acute plaque change with thrombosis, vasospasm or combinations. Other contributors are anemia, hypotension, tachycardia and hypertrophy. The syndromes are stable angina, unstable angina, myocardial infarction, sudden cardiac death and chronic ischaemic heart disease with heart failure.
Structure
- Chronic ischaemic heart disease: heavy, dilated heart; multiple grey-white scars; severe coronary atherosclerosis; subendocardial myocyte vacuolisation (myocytolysis) from chronic ischemia.
Step by step
- Atherosclerotic plaques narrow the coronary arteries; flow is adequate at rest.
- With effort, demand rises; above about 70 % stenosis supply cannot keep up: stable angina.
- A plaque ruptures or erodes; platelets and thrombus partially block the artery: unstable angina.
- If the thrombus occludes the vessel long enough, myocytes die: myocardial infarction.
- Ischemia can trigger ventricular fibrillation at any stage: sudden cardiac death.
- Repeated infarcts and ischemia lead to scarring, dilation and chronic heart failure.
The ischaemic syndromes and their lesions
| Syndrome | Coronary lesion | Myocardium | Pattern |
|---|---|---|---|
| Stable angina | Fixed stenosis (around 70 % or more) | Reversible ischemia | Effort pain, relieved by rest |
| Unstable angina | Disrupted plaque with non-occlusive thrombus | Ischemia, small foci of necrosis may occur | Rest or crescendo pain |
| Vasospastic angina | Spasm, often near a plaque | Transient transmural ischemia | Rest pain at night, ST elevation |
| Myocardial infarction | Occlusive or near-occlusive thrombus | Necrosis | Prolonged pain, troponin rise |
Clinical notes
- Ischaemic heart disease is the leading cause of death worldwide and in Colombia.
- Stunned myocardium recovers in days after reperfusion; hibernating myocardium recovers only after flow is restored.
Test yourself
Think of the answer, then tap the question to see it.
What is the usual pathological basis of unstable angina?
Disruption of an atherosclerotic plaque with a superimposed non-occlusive (partial) thrombus, sometimes with emboli.
What is hibernating myocardium?
Chronically underperfused myocardium that reduces its contraction to survive and recovers function when blood flow is restored.
Which three syndromes form the acute coronary syndromes?
Unstable angina, acute myocardial infarction and sudden cardiac death triggered by acute plaque change.
Elsewhere in DurgiPedia
- Coronary circulation and myocardial ischemia
- Chest pain: ischemic, pericardial, pleural and other patterns
- The ECG in ischemia and infarction
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Coronary Artery Disease | CAD | MedlinePlus (MedlinePlus, US National Library of Medicine, 2025); Coronary heart disease: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.