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It is not possible to give a specific answer / You have not said where is the hole!? - probably atrial septal defect?
The decision and mode of treatment depends on several factors - size is only one
There are risks to any surgery / there are also risks in not doing surgery - Pulmonary hypertension; paradoxical embolism
/ Infection may come even without operation - Infective Endocarditis
Wishing speedy recovery