left-ventricular noncompactionA recently described and increasingly recognised postnatal persistence of the pattern of embryonic myoarchitecture resulting in a cardiomyopathy characterised by intrauterine arrest of compaction of the myocardial fibres and meshwork—a critical step in myocardial development—resulting in an altered myocardial wall with prominent trabeculatios, deep intertrabecular recesses, and a thickened ventricular myocardium with two layers consisting of compacted and noncompacted myocardium.
Progressive systolic failure, stroke, arrhythmia, embolic events, and sudden cardiac death due to right and left ventricular failure. Other findings include facial defects, developmental delay, cleft palate, cataract.
Echocardiography; the diagnosis is often delayed due to lack of recognition.
Noncompacted myocardium with intramyocardial sinusoids and coronary artery fistulae may be associated with congenital right or left ventricular outflow tract defects—e.g., pulmonary atresia with intact ventricular septum—but, unlike left-ventricular noncompaction, are often associated with coronary artery defects. Noncompacted myocardium may accompany other congenital cardiac diseases (e.g., Ebstein's anomaly, bicuspid aortic valve, aorta-to-left ventricular tunnel, congenitally corrected transposition, isomerism of the left atrial appendage, ventricular septal defects, cardiomyopathies due to neuromuscular disorders), metabolic diseases and genetic syndromes (e.g., Barth syndrome, Charcot-Marie-Tooth disease 1A, Melnick-Needles syndrome, and nail-patella syndrome).