Thelansis

  Hypoplastic left heart syndrome (HLHS) is a complex combination of cardiac malformations that probably results from multiple developmental errors in the early stages of cardiogenesis and that, if left untreated, invariably prove fatal. A variety of chest radiographic findings is seen in patients with HLHS, including an enlarged cardiac silhouette (notably a prominent right atrium), pulmonary venous hypertension, an atrial septal defect, and valvular stenosis or atresia. In HLHS, pulmonary venous blood enters the left atrium, but atrial systole cannot push blood across the atretic or stenotic mitral valve into the hypoplastic left ventricle. Consequently, left atrial blood is shunted across interatrial communication. The interatrial defect can range from a highly restrictive pinhole-sized foramen ovale to a wide, nonrestrictive atrial septal defect. Most commonly, the foramen ovale restricts left-to-right shunting. This restricted flow, coupled with decreased flow through the mitr...