The prognosis depends on the presence and severity of associated anomalies. If an isolated VSD is small, the prognosis is good. Many such defects close spontaneously. Frequently this defect is associated with other cardiac and extracardiac abnormalities, and there has been an association between ASDs and chromosome abnormalities, especially trisomy 21. Prognosis is usually poor, because of the high incidence of associated anomalies and chromosome abnormalities.
Diagnosis is made by diminished left ventricle size in comparison to right ventricle size.
Also, aortic atresia and hypoplasia of the ascending aorta may be visualized. The prognosis for this condition is poor without transplant. The etiology of HLHS is not known, but the recurrence risk is approximately 4 percent after the birth of one affected infant. Hypoplasia of the right ventricle is secondary to this obstruction. Sonographic findings of this condition are diminished right ventricle volume in comparison to the left ventricle and atresia or hypoplasia of the pulmonary artery.