Mechanical complications of myocardial infarction
Mechanical complications of myocardial infarction are catastrophic structural ruptures, papillary muscle rupture, ventricular septal rupture, and free-wall rupture, occurring days after a usually large, late-reperfused infarct and presenting as abrupt hemodynamic collapse, often with a new murmur. Diagnosis is by urgent echocardiography, and survival depends on hemodynamic stabilization and emergent surgical repair.
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What this article covers
- Overview
Definition: mechanical complications of myocardial infarction are structural ruptures of infarcted myocardium, comprising papillary muscle rupture, ventricular septal rupture, and left ventricular free-wall rupture.
- Epidemiology
Uncommon but highly lethal, and less frequent in the reperfusion era.
- Risk factors
Large transmural infarct with a first, single-territory event (no protective collaterals).
- Pathophysiology
Necrosis weakens myocardium: infarcted tissue softens over days, and neutrophil-mediated remodeling around day 3 to 5 makes it prone to rupture.
- Clinical features
Papillary muscle rupture: sudden pulmonary edema and hypotension with a new holosystolic (mitral) murmur.
- Differential diagnosis
Recurrent or extending infarction: recurrent chest pain with ischemic ST changes, distinguished by the absence of a new murmur, shunt, or structural defect on echocardiography (STEMI).
- Diagnosis
Establish with urgent echocardiography identifying the specific rupture: the diagnostic basis is transthoracic (and, if needed, transesophageal) echocardiography demonstrating acute severe mitral…
- Management
First, stabilize hemodynamics as a bridge to surgery: Afterload reduction with sodium nitroprusside (start 0.3 mcg/kg/min IV, titrate) when blood pressure permits.
- Complications
Death: high mortality, particularly with free-wall rupture.
- Prognosis
Poor without surgery: medical management alone carries very high mortality.
- Prevention
Timely reperfusion of STEMI (primary PCI within 90 minutes) limits infarct size and is the main preventive measure.
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