Response to letter regarding article, "mortality and sudden death in pediatric left ventricular noncompaction in a tertiary referral center".

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.