Fetal bradycardia associated with left ventricle noncompaction diagnosed as HCN4 mutations

Abstract

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.

Keywords

• cardiac channelopathy
• fetal echocardiography
• hcn4 gene
• left ventricle noncompaction cardiomyopathy
• sick sinus syndrome