Clinical Characteristics and Prognosis of Fetal Left Ventricular Noncompaction in Japan

Fetal bradycardia associated with left ventricle noncompaction diagnosed as HCN4 mutations

A 35-year-old pregnant woman was referred to our hospital because of fetal bradycardia. Fetal echocardiography revealed a normal fetal heart except for slightly prominent trabeculae in the left ventricle, normal cardiac function, and fetal sinus bradycardia with a heart rate of 100 bpm. Electrocardiography (ECG) after birth revealed sinus bradycardia with a heart rate of 70-80 bpm. Transthoracic echocardiography revealed left ventricular noncompaction localized in the apex with normal cardiac function. A 24-h Holter ECG showed a heart rate range of 62-169 bpm without a pause of more than 2 s. A genome analysis performed during the neonatal period revealed a heterozygous inflame variant p.(Ser672_Asp676del)[chr15:g. 73324203_733242] in HCN4 gene. Fetuses with a heart rate less than the 3rd percentile of the gestational age should be followed and screened for congenital heart disease and cardiomyopathy. In addition, inherited arrhythmia syndrome should be considered.

A case of fetal isolated ventricular noncompaction with TNNT2 gene mutation and literature review

BACKGROUND

Ventricular noncompaction (VNC) is a cardiomyopathy characterized by overdeveloped ventricular trabeculaes and deep recess, which has been rarely reported.

CASE PRESENTATION

A 29-year-old Chinese pregnant woman with no obvious fetal abnormality in regular prenatal examination during first and second trimester. However, at 32 weeks of gestation, both obstetric growth scan and fetal echocardiogram revealed an enlarged heart with grid-like changes at the apical region. Eventually, the genetic and autopsy findings indicated the deceased infant with VNC.

CONCLUSION

Isolated VNC could be detected prenatally, even during the late pregnancy. Fetuses suspected of VNC should be offered genetic tests.

Left ventricular noncompaction: a disorder with genotypic and phenotypic heterogeneity-a narrative review

Background and Objective

Left ventricular noncompaction (LVNC) is a cardiomyopathy characterized by excessive trabecular formation and deep recesses in the ventricular wall, with a bilaminar structure consisting of an endocardial noncompaction layer and an epicardial compacted layer. Although genetic variants have been reported in patients with LVNC, understanding of LVNC and its pathogenesis has not yet been fully elucidated. We addressed the latest findings on genes reported to be associated with LVNC morphogenesis and possible pathologies to understand the diverse spectrum between genotype and phenotype in LVNC. Also, the latest findings and issues related to the diagnosis of LVNC were summarized.

Methods

This article is written as a commentary narrative review and will provide an update on the current literature and available data on common forms of LVNC published in the past 30 years in English through to May 2022 using PubMed.

Key Content and Findings

Familial forms of LVNC are frequent, and autosomal dominant mode of inheritance has been predominantly observed. Several of the candidate causative genes are also mutated in other cardiomyopathies, suggesting a possible shared molecular and/or cellular etiology. The most common gene functions were sarcomere function whereas genes in mice LVNC models were involved in heart development. Echocardiography and cardiac magnetic resonance imaging (CMR) are useful for diagnosis although there are no unified criteria due to overdiagnosis of imaging, poor consistency between techniques, and lack of association between trabecular severity and adverse clinical outcomes.

Conclusions

This review reflects the current lack of clarity regarding the pathogenesis and significance of LVNC and showed the complexity of imaging diagnostic criteria, interpretation of the role of LVNC as a cause, and uncertainty regarding the specific genetic basis of LVNC.