SIGNOS RADIOGRAFICOS: Tetralogy of Fallot and Boot-shaped Heart

The four established components of tetralogy of Fallot, which was first described in 1888 by
French physician Etienne-Louis Arthur Fallot, include (a) ventricular septal defect, (b) infundibular pulmonary stenosis, (c) overriding aorta, and (d) right ventricular hypertrophy. The current understanding of the embryologic origin of this syndrome is that it results from a single defect, an anterior malalignment of the conal septum, which in turn causes ventricular septal defect, right ventricular outflow tract obstruction, and overriding aorta. Right ventricular hypertrophy typically develops in long-standing untreated disease. Tetralogy of Fallot accounts for 10%– 11% of cases of congenital heart disease. On chest radiographs in those affected by this syndrome, the heart has the shape of a wooden shoe or boot (in French, coeur en sabot) (Fig 5). This deformity is due to uplifting of the cardiac apex because of right ventricular hypertrophy and concavity of the main pulmonary artery. The shadow of the pulmonary arterial trunk is almost invariably absent, and blood flow to the lungs is usually reduced. The right ventricular infundibulum often forms a slight bulge in the upper left heart border, while the middle left heart border is usually concave. Approximately 25% of those affected by tetralogy of Fallot have a right-sided aortic arch (1– 4,19) (Fig 5a). Overall, the most common radiologic finding in tetralogy of Fallot is an upturned cardiac apex, and the more severethe obstruction of the right ventricular outflowtract, the more pronounced that deformity.