BACKGROUND: Left ventricular noncompaction is a cardiomyopathy characterized by 
excessive trabeculation of the left ventricle, progressive myocardial 
dysfunction, and early mortality. Left ventricular noncompaction has a 
heterogeneous clinical presentation that includes arrhythmia and sudden cardiac 
death.
METHODS AND RESULTS: We retrospectively reviewed all children diagnosed with 
left ventricular noncompaction at Texas Children's Hospital from January 1990 to 
January 2009. Patients with congenital cardiac lesions were excluded. Two 
hundred forty-two children were diagnosed with isolated left ventricular 
noncompaction over the study period. Thirty-one (12.8%) died, and 13 (5.4%) were 
received a transplant. One hundred fifty (62%) presented with or developed 
cardiac dysfunction. The presence of cardiac dysfunction was strongly associated 
with mortality (hazard ratio, 11; P<0.001). ECG abnormalities were present in 
87%, with ventricular hypertrophy and repolarization abnormalities occurring 
most commonly. Repolarization abnormalities were associated with increased 
mortality (hazard ratio, 2.1; P=0.02). Eighty children (33.1%) had an 
arrhythmia, and those with arrhythmias had increased mortality (hazard ratio, 
2.8; P=0.002). Forty-two (17.4%) had ventricular tachycardia, with 5 presenting 
with resuscitated sudden cardiac death. In total, there were 15 cases of sudden 
cardiac death in the cohort (6.2%). Nearly all patients with sudden death (14 of 
15) had abnormal cardiac dimensions or cardiac dysfunction. No patient with 
normal cardiac dimensions and function without preceding arrhythmias died.
CONCLUSIONS: Left ventricular noncompaction has a high mortality rate and is 
strongly associated with arrhythmias in children. Preceding cardiac dysfunction 
or ventricular arrhythmias are associated with increased mortality. Children 
with normal cardiac dimensions and normal function are at low risk for sudden 
death.