Cardiomyopathy Phenotypes and Outcomes for Children With Left Ventricular Myocardial Noncompaction: Results From the Pediatric Cardiomyopathy Registry

Abstract

Background Left ventricular noncompaction (LVNC) is a distinct form of cardiomyopathy characterized by hypertrabeculation of the left ventricle. The LVNC phenotype may occur in isolation or with other cardiomyopathy phenotypes. Prognosis is incompletely characterized in children. Methods and Results Using diagnoses from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry from 1990-2008, 155 of 3219 children (4.8%) had LVNC. Each LVNC patient was also classified as having an associated echocardiographically diagnosed cardiomyopathy phenotype (dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), isolated, or indeterminate). The time to death or transplant differed among the phenotypic groups (P = 0.035). Time to listing for cardiac transplantation significantly differed by phenotype (P < 0.001), as did time to transplantation (P = 0.015). The hazard ratio for death/transplant (with isolated LVNC as the reference group) was 4.26 (95% confidence interval [CI], 0.78 to 23.3) for HCM, 6.35 (95% CI, 1.52 to 26.6) for DCM, and 5.66 (95% CI, 1.04 to 30.9) for the indeterminate phenotype. Most events occurred in the first year after diagnosis. Conclusion LVNC is present in at least 5% of children with cardiomyopathy. The specific LVNC-associated cardiomyopathy phenotype predicts the risk of death/transplant and should inform clinical management.

Pediatric Cardiomyopathies

“…20 In the PCMR, NCM accounted for 4.8% of pediatric cardiomyopathies, although more than twice as many children were diagnosed in the most recent era suggesting that as the definition of NCM becomes standardized, the true incidence may be higher than previously appreciated. 21 NCM may occur as an isolated phenotype (23%), a mixed NCM/DCM phenotype (59%), a mixed NCM/HCM phenotype (11%), or an indeterminate phenotype (8%). 21 …”

Decreased Deformation in Asymptomatic Children with Isolated Left Ventricular Non-compaction and Normal Ejection Fraction

“…Also, hypertrophic cardiomyopathy and restrictive cardiomyopathy cases were reported in the 2-year follow-up in the patients with iLVNC [15]. Early detection of ventricular dysfunction and arrhythmias can reduce the risk of sudden death [4].…”

Mechanisms of Trabecular Formation and Specification During Cardiogenesis

“…This trabecular zone coalesce with the compact zone is called the trabecular compaction, starting at the base of the heart and progressing toward the apex 3 . Disturbed compaction during development results in left ventricular noncompaction (LVNC) 3,7,8 . About half a million Americans suffer from LVNC 9 .…”