I know I'm late, but oh well. I'm a pediatric anesthesiologist who participates in the open-heart repair and subsequent procedures. Not at all aviation related, however, so you will want to be examined.
Most likely, I would guess no go, however. Tet repairs have varying levels of subsequent morbidity based around the severity of the original anatomic defect, the type and quality of the repair, how early in life it was done and if before major cardiopulmonary sequelae. However, even good anatomic repairs that will likely lead to a long life have an increased risk of arrythmias and sudden cardiac death.