How long of a surgery is needed to correct a tetralogy of fallot?

Depends: The surgery to correct this heart problem may not be able to be performed in one surgery, but may involve several steps. Depending on the child's condition at birth the complexity may require a lengthy initial procedure. There is not one answer, sorry. Prenatal diagnosis before delivery is essential for immediate treatment.

Several hours: The thinking nowadays is to try and correct the defect in the newborn period if possible or at least within the first 2-3 months. In the past tetralogy of fallot was repaired in two steps, a simple surgery within the first several months to connect blood from a branch of the aorta to the lung arteries followed by complete repair at 3-5 years of age.