What is the outcome of av canal surgery ?

Depends: It depends on what's done.

Excellent for most: Av canal is a heart defect that requires surgery to repair. Most babies do not develop symptoms until 3-4 weeks of age. Surgery is usually done around 3-6 months of age. Though it is open heart surgery, the vast majority of children do well, in the hands of an experienced surgical center. After repair, children require lifelong follow up but most have no restrictions.

Some variation: Some are more extensive. So depending on size of septal defects and valvular involvements the corrective repair on cardiopulmonary bypass can be variable. Generally good results are possible.