How does anyone know someone has hypoplastic left heart syndrome?

Echocardiogram: An infant will be suspected as having heart defect by examination and pulse oximetry. A pediatric cardiologist will perform an echocardiogram to make the diagnosis. The infant may appear very normal on the outside. Once changes occur in the newborn infant hlhs is not compatible with life without surgical intervention. A fetal echo by an experienced ped cardiologist can id this before birth.

Yes, lots of kids: I'm a pediatric cardiologist and caediac intensive care physician at one of the largest congenital heart programs in the country, so i've taken care of many children with hypoplastic left heart syndrome.