Simplified systemic hemodynamics in (A) normal fetal circulation, (B) d-transposition of the great arteries (d-TGA) and (C) hypoplastic left heart syndrome (HLHS).
Black arrows represent the blood flow. Yellow arrows represent the cerebral blood supply. The pulmonary circulation is not included because the blood flow to the lungs is highly limited due to elevated pulmonary vascular resistance and relatively low lung volume prior to birth. DA, ductus arteriosus; FO, foramen ovale; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; PT, pulmonary trunk; RA, right atrium; RV, right ventricle; SVC, superior vena cava. Adapted from Sun et al. [51] with permission of the publishers.