Non-compaction of the left ventricle
Non-compaction of the left ventricle, also known as spongiform cardiomyopathy, is an arrest of myocardial compaction during embryogenesis, leading to hypertrophic ventricular trabeculations and deep inter-ventricular recesses.
This abnormality has also been described in the right ventricular, but it is much rarer 3.
The diagnosis is usually made in late stages of the disease when a patient presents with congestive heart failure. Other clinical findings include ventricular arrhythmias and thromboembolic events. However, patients with only mild left ventricular (LV) non-compaction may be completely asymptomatic.
In most patients with non-compaction of the left ventricle, there are no other cardiac malformations. Familial and sporadic form have been described 1. However, in at least one study, approximately 12% of patients had associated cardiac malformations 1:
- ventricular outflow tract abnormalities (46%, mainly bicuspid aortic valve)
- Ebstein anomaly (25%)
- more rarely: tetralogy of Fallot or coarctation of the aorta
Chest radiographs are not useful in the diagnosis of non-compaction of the left ventricle. They are more useful in identifying complications of the cardiomyopathy, such as pulmonary oedema and cardiomegaly.
Echocardiography was traditionally used in the diagnosis of LV non-compaction. However, cardiac MRI is now considered the modality of choice to make this diagnosis. There are no universally accepted echocardiographic criteria for LV non-compaction. Main criteria include:
- deep interventricular recesses seen with colour Doppler
- prominent trabecular meshwork
- a ratio of non-compacted telesystolic myocardium to compacted telesystolic myocardium of 2:1 (measurements made in parasternal short axis view).
Also, both systolic and diastolic dysfunction may be seen.
Cardiac MRI has a better contrast resolution than echocardiography and it is the modality of choice for the diagnosis of spongiform cardiomyopathy. The best diagnostic clue is a ratio of non-compacted telediastolic myocardium to compacted telediastolic myocardium of more than 2.3:1 (sensitivity: 86%, specificity: 99%).
Treatment and prognosis
The only definitive treatment of LV noncompaction is cardiac transplantation. Otherwise, prevention of both heart failure and thromboembolic events are the main target of treatments.
Possible differential considerations in certain situations include:
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