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Tetralogy of Fallot (ToF) is the most common cyanotic congenital heart disease (CHD). The history of surgical treatment of ToF is closely linked with the origins of cardiac surgery. Before the era of cardiac surgery, most ToF patients died in childhood; now well over 85% survive to adulthood, resulting in an increased prevalence of ToF in adults.1 Patients with “repaired” ToF pose unique challenges for primary care providers and cardiologists. This review will focus on the history and changing epidemiology of ToF in adults, the pathophysiology of repaired ToF, and emerging data for monitoring and treatment.
The aorta and pulmonary artery form from septation of the distal bulbus cordis and truncus arteriosus and rotate to overlie the ventricles. Faulty rotation and septation with incomplete transfer of the aorta to a position above the left ventricle results in a malalignment ventricular septal defect (VSD) and an aorta that “overrides” the interventricular septum.w1 Right ventricle (RV) outflow tract obstruction, the other defining feature of ToF, is the result of one or more of the following abnormalities: subvalvar obstruction from septal deviation, hypertrophied muscular bands in the RV outflow tract, a hypoplastic pulmonary valve annulus, pulmonary valve stenosis or atresia, and main or branch pulmonary artery stenosis. The RV hypertrophies as a result of the outflow tract obstruction. Thus, the characteristic four features of ToF are an overriding aorta, RV outflow tract obstruction, malalignment VSD, and RV hypertrophy (fig 1). In addition, ToF is associated with other congenital cardiac abnormalities in about 40% of patients. Some of the more common anomalies are a right sided aortic arch (13–34%), atrial septal defect (∼15%), atrioventricular septal defect (1.7–7%), anomalous coronary arteries (most commonly a prominent conus artery or the left anterior descending artery from the right coronary artery or right sinus of Valsalva) …