Pediatric Cardiology and Cardiac Surgery
Vol.25 No.1 2009 (16-22)

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Sayaka Watanabe, Kazuyoshi Saitoh, Keijiro Ibuki, Kazuhiro Watanabe, Keiichi Hirono, Keiichiro Uese, Fukiko Ichida, and and Toshio Miyawaki

Department of Pediatrics, University of Toyama Graduate School of Medicine, Toyama, Japan


Background: Isolated noncompaction of left ventricular myocardium (INVM) is characterized by a left ventricle with a prominent trabecular meshwork, thought to be due to an arrest of myocardial morphogenesis during fetal life. However, an increasing number of juvenile or adult cases, with longer clinical courses, have been reported.
Methods: We compared the clinical features and anatomical properties of infantile cases of INVM (< 2 years: 43 cases) with juvenile cases (2-15 years: 45 cases). We developed an echocardiographic criteria-based “noncompaction score” to estimate the severity of noncompacted myocardium, in addition to the standard noncompacted to compacted layer (N/C) ratio. Results: Although most patients in the infantile group had clinical signs or symptoms of heart failure at initial presentation (63%), the majority of juvenile cases were asymptomatic and identified only when screened for cardiac abnormalities, such as electrocardiogram (ECG) screening (60%). While the incidence of Wolff-Parkinson-White (WPW) syndrome was higher (16.4%) in both groups, the incidence of left bundle blanch block (LBBB) and ventricular tachycardia (VT) was lower than those reported in adults. On echocardiography, the maximum N/C ratio was observed at the apex in both groups. Neither noncompaction score nor N/C score was significantly different between groups. Left ventricular ejection fraction (LVEF) at initial presentation was significantly lower in the infantile group than in the juvenile group. Although survival analysis showed poor prognosis in the infantile group, the significant risk factors were LVEF below 50% (p = 0.008, HR = 18.8), and clinical signs of heart failure at diagnosis (p = 0.008, HR = 13.4), rather than age of onset. Conclusions: INVM in both groups showed poor prognosis when correlated with depressed LVEF and heart failure at diagnosis.