An animation depicting the anterior view of the heart and pulmonary system before and after birth. Normal fetal anatomy in this view includes the ductus arteriosus, pulmonary artery, atriums, ventricles, and the lungs. Before birth, the lungs of the fetus do not function in the womb and therefore the ductus arteriosus allows blood to be shunted away from the pulmonary artery to the aorta before it reaches the lungs. Normally, after birth the baby starts to breathe and the ductus arteriosus closes to allow for blood flow into the lungs. In this patient's case, the ductus arteriosus remained open after birth and an atrial septal defect in the wall between the upper chambers of the heart allowed blood to be shunted from the left side of the heart to the right side, causing excess circulation in the pulmonary system and mild dilation of the right heart.
