: 100–101  Although males and females were initially believed to be affected equally, more recent studies have shown TOF affects males more than females. About 1 in 100 newborns is diagnosed with a congential heart defect, of which 10% are diagnosed with TOF. Genetically, it is most commonly associated with Down syndrome and DiGeorge syndrome. Down syndrome and other chromosomal disorders are known to occur alongside congential heart defects such as TOF. History
Tetralogy of Fallot was initially described in 1671 by the Danish researcher Niels Steensen. Also referenced as Nicolaus Steno in Latin, Stensen was a pioneer in anatomy and geology. His work made significant contributions to the field of cardiac anatomy and pathology, which led to the condition initially being titled Steno-Fallot tetralogy. A further description was published in 1888 by the French physician Étienne-Louis Arthur Fallot, after whom it was ultimately named. In 1924, Maude Elizabeth Seymour Abbott, a pediatric cardiologist from Montreal, Canada, named it tetralogy of Fallot.The short paper "Dissection of a Monstrous Foetus in Paris" in 1671 first described the conditions that would later together be known as TOF. In particular, it highlighted the unusual formation of arteries, the stenosing of the pulmonary artery, the absence of the ductus arteriosus, an overriding aorta, and fetal cardiac circulation where blood was redirected to the aorta from the pulmonary artery. Over a hundred years later in 1777, Dutch physician Eduard Sandifort reported what he referred to as "the blue boy" patient.
: 153 Timing of surgery in asymptomatic patients is usually between the ages of two months to one year. : 201–2  However, in symptomatic patients showing worsening blood oxygen levels, severe tet-spells (cyanotic spells), or dependence on prostaglandins from early neonatal period (to keep the ductus arteriosus open) need to be planned fairly urgently: 201–2 Potential surgical repair complications include residual ventricular septal defect, residual outflow tract obstruction, complete atrioventricular block, arrhythmias, aneurysm of right ventricular outflow patch, and pulmonary valve insufficiency. : 59  Long-term complications most commonly include pulmonary valve regurgitation, and arrhythmias.Total repair of tetralogy of Fallot initially carried a high mortality risk, but this risk has gone down steadily over the years. Surgery is now often carried out in infants one year of age or younger with less than 5% perioperative mortality. : 205  Post surgery, most patients enjoy an active life free of symptoms. : 205  Currently, long-term survival is close to 90%. : 167  Today the adult TOF population continues to grow and is one of the most common congenital heart defects seen in adult outpatient clinics. : 100–101

Palliative surgery
Initially surgery involved forming a side to end anastomosis between the subclavian artery and the pulmonary artery -i.e. a systemic to pulmonary arterial shunt. : 57  This redirected a large portion of the partially oxygenated blood leaving the heart for the body into the lungs, increasing flow through the pulmonary circuit, and relieving symptoms.