TOPICS: Systemic atrial circulation, systemic venous blood, ventricular septal defect (VSD), primum atrial septal defect (ASD), secundum atrial septal defect (ASD), patent ductus arteriosus (PDA), cyanosis, Eisenmenger syndrome, pulmonary vascular resistance, congenital heart defects, bicuspid aortic valve, Eisenmenger syndrome, holosystolic murmur, fetal alcohol syndrome, down syndrome, septum primum, endocardial cushion, AV canal defects, septum secundum, fossa ovalis, foramen ovale, interatrial septum formation, interatrial defects, pulmonic valve, fixed split of S2, systolic ejection murmur, sixth aortic arch, prostaglandin E2, congenital rubella, machine-like murmur, cyanosis, pulse pressure