Definition

An aneurysm is a section of defective wall that bulges outward

A ventricular aneurysm is a defect in the left (or right) ventricle of the heart, usually produced by transmural infarction

Aneurysm formation occurs when intraventricular tension stretches the non-contracting infarcted myocardium, causing bulging of the infarcted area with each contraction

The wall of the true LV aneurysm is thinner than the wall of the rest of the left ventricle and is usually composed of fibrous tissue as well as necrotic muscle, sometimes mixed with viable myocardium

Causes persistent ST Elevation following the acute MI

Background

Following an acute STEMI, the ST segments return towards baseline over a period of two weeks, while the Q waves persist and the T waves usually become flattened or inverted

However, some degree of ST elevation remains in 60% of patients with anterior STEMI and 5% of patients with inferior STEMI

The mechanism is thought to be related to incomplete reperfusion and transmural scar formation following an acute MI

This ECG pattern is associated with paradoxical movement of the ventricular wall on echocardiography (ventricular aneurysm)

ECG Features of LV Aneurysm

ST elevation seen > 2 weeks following an acute myocardial infarction
- Most commonly seen in the precordial leads (v1-v6)

These may exhibit concave or convex morphology

Usually associated with well-formed Q- or QS waves

T-waves have a relatively small amplitude in comparison to the QRS complex (unlike the hyperacute T-waves of acute STEMI)

Example ECG

Minimal ST elevation in V1-3 associated with deep Q waves and T-wave inversion
This is a LV aneurysm secondary to a prior anteroseptal STEMI

Clinical Significance

Ventricular arrhythmias and sudden cardiac death
(myocardial scar tissue is arrhythmogenic)

Death is often sudden and may be related to the high incidence of ventricular tachyarrhythmias associated with LV aneurysms

The rate of mortality in patients with LV aneurysms is up to 6x higher than in patients without aneurysms

Congestive cardiac failure

Mural thrombus and subsequent embolisation

Rupture of aneurysm is rare (the rupture rate is higher with pseudoaneurysms)

Causes

- Acute myocardial infarction (by far the most common)
- Cardiomyopathy
- Cardiac infection
- Congenital abnormalities

Quiz

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