Fetal Functionally Single Ventricle

Single ventricle congenital heart disease is a heterogeneous group of lesions with a wide variety of postnatal physiology and management strategies – prenatally, this is similar. While most single ventricle lesions are well tolerated in utero, counseling expectant families on prenatal monitoring and interventions (when available), delivery planning, and the expected postnatal course can be challenging due to the broad array of possible outcomes. The fetal echocardiogram is an essential part of the evaluation to accurately guide families on what to expect and to ensure appropriate monitoring of the fetus prior to delivery. In addition to providing diagnostic anatomic information, fetal echocardiography assesses prenatal hemodynamics that can inform how the infant will transition to extrauterine life and thus guide special planning or resources that may be needed. In this chapter, we will discuss the prenatal evaluation and management, delivery planning considerations, and anticipated immediate postnatal course of fetuses with congenital heart lesions that frequently result in a postnatal single ventricle physiology. In this chapter, we will review several functionally single ventricle lesions; this includes pulmonary atresia with intact ventricular septum, unbalanced atrioventricular canal defect, tricuspid atresia, and double-inlet left ventricle. Hypoplastic left heart syndrome will be reviewed in a separate chapter dedicated to this lesion.