Definition Patients with hypoplastic left heart syndrome (HLHS) have some combination of aortic and mitral atresia or stenosis, which due to decreases in flow, leads to underdevelopment of the left ventricle. The single right ventricle (RV) provides systemic blood flow from the pulmonary artery (PA) to the aorta via a patent ductus arteriosus. Prostaglandin E1 […]