Rapid Review·Cardiovascular
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PATHOLOGY
T2High yieldMyocardial Infarction Complications
P313
Focus on
Which complication happens when, and why the timing is mechanistic rather than arbitrary.
Key takeaways
The complications, in the order they happen
Cardiac arrhythmia, first few days to several months
supraventricular, ventricular, or conduction blocks, from myocardial death and scarring. An important cause of death before reaching hospital and within the first 48 hours.Peri-infarction pericarditis, 1 to 3 days
pleuritic chest pain, friction rub, ECG changes, small effusion. Usually self-limited.Papillary muscle rupture, 2 to 7 days
acute mitral regurgitation causing cardiogenic shock and severe pulmonary edema. Posteromedial far more often than anterolateral, because the posteromedial has a single blood supply from the PDA while the anterolateral has dual supply from the LAD and LCX.Interventricular septal rupture, 3 to 5 days
macrophage-mediated degradation creates a VSD, so oxygen saturation and pressure step up in the RV. Symptoms range from mild to cardiogenic shock with pulmonary edema.Ventricular pseudoaneurysm, 3 to 14 days
a free wall rupture contained by adherent pericardium or scar. It contains no endocardium or myocardium, which is why it is more likely to rupture than a true aneurysm. May be silent, or cause chest pain, a murmur, arrhythmia, syncope, heart failure, or an embolus from mural thrombus.Ventricular free wall rupture, 5 to 14 days
causes cardiac tamponade or internal hemorrhage; the acute form usually means sudden death. LV hypertrophy and prior scar can be protective.True ventricular aneurysm, 2 weeks to several months
an outward bulge during contraction, i.e. dyskinesia. Associated with fibrosis and mural thrombus.Postcardiac injury (Dressler) syndrome, weeks to months
autoimmune fibrinous pericarditis. Cardiac antigens released after injury drive immune complex deposition in the pericardium.| Complication | Timeframe | Mechanism |
|---|---|---|
| Cardiac arrhythmia | First few days to months | Myocardial death and scarring |
| Peri-infarction pericarditis | 1 to 3 days | Inflammation adjacent to epicardium |
| Papillary muscle rupture | 2 to 7 days | Macrophage degradation; posteromedial has single PDA supply |
| Interventricular septal rupture | 3 to 5 days | Macrophage degradation creating a left-to-right shunt |
| Ventricular pseudoaneurysm | 3 to 14 days | Rupture contained by pericardium or scar |
| Free wall rupture | 5 to 14 days | Tamponade, often fatal |
| True ventricular aneurysm | 2 weeks to months | Fibrosis, with mural thrombus |
| Dressler syndrome | Weeks to months | Autoimmune immune complex deposition |
| Feature | True ventricular aneurysm | Pseudoaneurysm |
|---|---|---|
| Wall contains | All layers, endocardium and myocardium included | Pericardium and scar only, no myocardium |
| Timing | 2 weeks to months | 3 to 14 days |
| Rupture risk | Lower | Higher |
| Finding | Dyskinetic outward bulge, mural thrombus | May rupture into tamponade |
| Feature | Peri-infarction pericarditis | Dressler syndrome |
|---|---|---|
| Timing | 1 to 3 days | Weeks to months |
| Mechanism | Direct inflammation next to the infarct | Autoimmune immune complex deposition |
| Course | Self-limited | May recur |
Treating the acute coronary syndrome
Unstable angina and NSTEMI
anticoagulation (heparin), antiplatelet (aspirin) plus an ADP receptor inhibitor (clopidogrel), cardioselective beta-blockers, ACE inhibitors, statins. Symptom control with nitroglycerin and morphine.STEMI
all of the above plus reperfusion, which matters most, with PCI preferred and fibrinolysis when PCI is not available.Inferior STEMI, hypotension, clear lungs. Nitroglycerin or fluids?
Fluids. The RV is infarcted and preload-dependent; nitroglycerin drops the preload it needs.
How it's tested
A right ventricular infarct from an RCA occlusion is preload-dependent, so nitroglycerin is exactly the wrong drug and the answer is IV fluids. That reversal of the usual ACS reflex is the highest-yield item here. The true versus pseudo aneurysm distinction rests entirely on what is in the wall: a pseudoaneurysm contains no myocardium at all, only pericardium and scar, which is why it is the one more likely to rupture despite being the smaller-sounding word.
Go deeper
First Aid 2026 — CV/Pathology (p.313) · B&B — Post-MI complications · Mehlman — HY Cardio (rupture timeline, Dressler, RV infarct and fluids)
Flashcards for this page
Card 1 of 5 · try-out only, nothing is saved
(...) oxygen saturation and pressure in the (...) ventricle from (...)-to-(...) shunting
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