Development of hypoplastic left heart syndrome after diagnosis of aortic stenosis in the first trimester by early echocardiography

Abstract

We describe a case of aortic stenosis in the first trimester that progressed to hypoplastic left heart syndrome. At 11 + 3 weeks' gestation the four-chamber view was normal but evidence of increased aortic blood velocity prompted the diagnosis of aortic outflow obstruction. At 16 + 6 weeks' gestation the left ventricle was hyperechogenic, globular and dysfunctional, suggesting the development of hypoplastic left heart syndrome. The aortic valve was small and there was no flow across the mitral or aortic valves. From 17 + 3 weeks increased reversed flow in the pulmonary veins suggested restriction of the foramen ovale. Follow-up echocardiographic examinations were performed every 2-3 weeks until delivery at term. Postnatal intervention included a Norwood I operation performed on the 5th postnatal day. We have shown the feasibility and utility of early fetal echocardiography and that a left heart obstruction diagnosed in the first trimester can progress to left heart hypoplasia during the early second trimester. This information is important for planning prenatal and perinatal management.