What is myocardial noncompaction, and how does it appear on MRI?
Noncompacted myocardium is a congenital abnormality in the structure of ventricular tissue due to a morphogenetic defect during embryogenesis. It seems to occur as a result of an arrest in endomyocardial morphogenesis. A family history of dilated cardiomyopathy is not uncommon. It manifests in early childhood, often associated with other cardiac and extracardiac anomalies. Clinical presentation includes ventricular dysrhythmias, thromboembolism, and progressive systolic heart failure, diastolic heart failure, or both. Myocardial noncompaction may be suggested when the ratio of the maximum thickness of the myocardial trabecular layer to compacted layer is ≥2.3 in end-diastole with a decreased ejection fraction in the absence of other types of structural heart disease.