Long-term prognosis of patients with left ventricular noncompaction: Comparison between infantile and juvenile types

Background: The natural history of left ventricular noncompaction (LVNC) is largely unsolved, so the aim of the present study was to clarify the clinical features and long-term prognosis of children with LVNC until adulthood. Methods and Results: We conducted a nationwide survey over 20 years and compared the clinical features, anatomical characteristics and long-term prognosis of 205 patients divided into 2 classifications: infantile type (diagnosed at <1 year of age: 108 cases) and juvenile type (diagnosed 1–15 years of age: 97 cases). Most patients diagnosed during infancy had heart failure (HF) at initial presentation (60.19%), while the majority of juvenile cases were asymptomatic (53.61%) but their event-free survival rate decreased gradually, because of later HF, thromboembolism and fatal arrhythmias. The initial LVEF was significantly lower in the infantile type and correlated with the thickness of the compacted layer in the LV posterior wall (LVPWC) and LV end-diastolic dimension (LVDD) Z-score, but not to the noncompacted to compacted layer (N/C) ratio. Survival analysis showed prognosis was similarly poor for both types after 2 decades. The significant risk factors for death, heart transplantation or implantable cardioverter-defibrillator insertion were congestive HF at diagnosis and lower LVPWC Z-score but not age of onset. Conclusions: LVNC of both types showed poor long-term prognosis, therefore ongoing follow-up is recommended into adulthood. HF at diagnosis and LVPWC hypoplasia are major determinants of poor prognosis.