The Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect. The morphologic key feature of TOF is the malalignment of the infundibular septum. The infundibular septum malalignment makes the aorta override interventricular septum (dextroposition) over a large ventricular septal defect (VSD) and promotes obstruction to the right ventricular infundibular tract. The pulmonary valve is also stenotic, and the pulmonary trunk and arteries are, to some degree, hypoplastic. Severe obstruction to pulmonary blood flow (PBF) leads to more […]