Left ventricular noncompaction (LVNC) is a cardiomyopathy characterized anatomically by deep trabeculations in the ventricular wall, which define recesses communicating with the main ventricular chamber. As in other cardiomyopathies, the clinical manifestations include systolic and diastolic dysfunction, associated at times with arrhythmia and systemic embolic events. The incidence and prevalence have not been well established; however, as the annual incidence of unclassified cardiomyopathy among children between 0 and 10 years of age is 0.17 per 100,000, the estimated incidence of LVNC in this age group can be calculated as 0.12 per 100,000. The definition and diagnostic criteria for this recently characterized condition are still under debate. The mechanisms that lead to LVNC are unclear but genetic predisposition has been suggested. The search for genes associated with LVNC is ongoing, and there is evidence for a role of mutations of the following genes: G4.5, Alpha-dystrobrevin, RyR2. Diagnosis can be made by echocardiography; current echocardiographic criteria for diagnosis typically include: presence of multiple echocardiographic trabeculations, multiple deep intertrabecular recesses communicating with the ventricular cavity, a two-layered structure of the endomyocardium with an increased noncompacted to compacted ratio. ECG features include biventricular hypertrophy with extreme QRS voltages, isolated or diffuse T-wave changes; Wolf-Parkinson-White syndrome with premature atrial and ventricular contractions. Medical treatment depends on the functional abnormalities (e.g., heart failure) and associated comorbidities, including systemic embolism and arrhythmia. Aspirin therapy is recommended for all patients to decrease the risk of systemic embolism.
Last update: September 2004