Postnatal manifestation of left heart failure following foetal-onset right heart failure in biventricular noncompaction with an MYH7 variant: a case report.

We report a case of foetal-onset biventricular noncompaction with an MYH7 variant. Prenatal fetal hydrops and right heart failure resolved after birth, but progressive left heart failure developed at 5 months. This transition reflects how postnatal hemodynamic changes influence the biventricular noncompaction phenotype, necessitating vigilant monitoring for left heart failure in foetal-onset biventricular noncompaction cases with MYH7 variants.