Complications of myocardial infarction
- Lesion
After a heart attack, different problems strike at different times: rhythm problems first, wall rupture in the first week, aneurysm and failure later.
What it is
The complications of myocardial infarction follow the healing timeline. In the first hours and days, arrhythmias and pump failure dominate. Between about the third and the tenth day the softened wall can rupture: the free wall (tamponade), the septum (acute VSD) or a papillary muscle (acute mitral regurgitation). Fibrinous pericarditis appears in transmural infarcts in the first days; autoimmune (Dressler) pericarditis weeks later. Mural thrombi, ventricular aneurysms and progressive heart failure come in the following weeks and months.
Structure
- Rupture: a slit-like tear through soft necrotic myocardium with surrounding haemorrhage.
- Aneurysm: a thin, fibrous, bulging wall without muscle, often lined by laminated thrombus.
- Infarct expansion: early stretching and thinning of the infarcted segment, which favours aneurysm and thrombus.
Complications of myocardial infarction on the healing timeline
| Complication | Usual timing | What happens |
|---|---|---|
| Arrhythmia | First hours to days | Ventricular fibrillation, tachycardia, heart block; sudden death |
| Cardiogenic shock | First days | Large infarct, low output |
| Free-wall rupture | Days 3–10 | Hemopericardium and tamponade |
| Papillary muscle rupture | Days 3–10 | Acute severe mitral regurgitation, pulmonary edema |
| Septal rupture | Days 3–10 | Acute VSD with left-to-right shunt |
| Fibrinous pericarditis | Days 1–3 | Friction rub over a transmural infarct |
| Ventricular aneurysm and mural thrombus | Weeks to months | Bulging scar, thromboembolism, arrhythmia, failure |
| Dressler syndrome | Weeks | Autoimmune pericarditis with fever and effusion |
Clinical notes
- Sudden hypotension with a new murmur after an infarct suggests papillary muscle or septal rupture; sudden pulseless electrical activity suggests free-wall rupture with tamponade.
Test yourself
Think of the answer, then tap the question to see it.
When is the risk of free-wall rupture highest after myocardial infarction, and why?
Around days 3 to 10, when macrophages have cleared the necrotic muscle but little collagen has been laid down.
Why is the posteromedial papillary muscle more vulnerable?
It usually has a single blood supply (from the posterior descending artery), while the anterolateral one has a dual supply.
What is Dressler syndrome?
A pericarditis appearing weeks after infarction or cardiac surgery, thought to be autoimmune, with fever and pericardial effusion.
Elsewhere in DurgiPedia
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: Heart Attack | Myocardial Infarction | MedlinePlus (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.