Dyspnea on exertion is common. These spells can be aborted with relatively simple procedures. The rare patient with TOF may remain marginally and imperceptibly cyanotic or acyanotic and asymptomatic into adult life. Severe cyanosis may present at birth in a patient with TOF and associated pulmonary atresia. Birth weight is low.
Retarded growth occurs.
Cyanosis and clubbing are variable. Squatting position Scoliosis is common. Ablation of cells of the neural crest has been shown to reproduce conotruncal malformations. These abnormalities are associated with the DiGeorge syndrome and branchial arch abnormalities. Oxygen saturation is variable, but pH and pCO 2 are normal unless the patient is in extremis, such as during a TET spell.