Ventricular remodelling and aneurysm after myocardial infarction
THE CONTEXT
Structural changes after myocardial infarction can progressively impair ventricular efficiency or produce an aneurysm with mechanical, electrical and embolic complications.
Mechanism and time course of remodelling
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After acute transmural myocardial infarction, thinning and stretching of the infarcted segment increase wall stress and cause progressive dilatation and hypertrophy of the remaining ventricle.
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The dilated ventricle becomes less efficient, and heart failure may develop.
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Infarct expansion occurs over days and weeks, whereas ventricular remodelling can take years.
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Beta-blockers, ACE inhibitors and mineralocorticoid receptor antagonists can reduce late ventricular remodelling and prevent heart failure.
Ventricular aneurysm
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Ventricular aneurysm develops in approximately 10% of patients with myocardial infarction and is particularly common with persistent occlusion of the infarct-related vessel.
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Recognised complications include heart failure, ventricular arrhythmias, mural thrombus and systemic embolism.
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Features include a paradoxical chest wall impulse, persistent ST elevation and sometimes an unusual bulge in the cardiac silhouette on chest X-ray.
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Echocardiography is diagnostic. Surgical removal of a left ventricular aneurysm is sometimes necessary despite high morbidity and mortality.