Tetralogy of Fallot

Tetralogy of Fallot is the most common cyanotic congenital heart disease in which there is ventricular septal defect, right ventricular outflow tract obstruction, aortic override of the ventricular septum, and right ventricular hypertrophy. The etiology is multifactorial, and genetics plays an important role, particularly with the association of 22q11.2 deletion. Clinical presentation often includes cyanosis that varies in severity depending on the degree of right ventricular outflow tract obstruction, which may range from ductal dependent pulmonary blood flow requiring prostaglandin infusion and surgery as newborn to minimal obstruction requiring more elective repair at 4–6 months. The diagnosis of tetralogy of Fallot is often made prenatally by fetal echocardiogram or by postnatal echocardiogram. Echocardiogram is the test of choice to define anatomic details and monitor peri-operative and postoperatively for residual lesions and complications. These can include pulmonary stenosis, regurgitation, branch pulmonary artery stenosis, and right ventricular dilation or dysfunction. Advanced imaging such as cardiac CT or MRI and cardiac catheterization may be needed in specific clinical scenarios.