Infant and open heart surgery?

my sisters son and his wife

have an infant 6 weeks old who just had open heart surgery this morning

when she was born she had a heart stint put in

now they say she is sedated and they don't want her to move at all

that she has an irregular heart beat after the surgery and if no change in the next couple of days they want to put in a pace maker

I know this is serious I am very concerned about her

Do you know of this happening to anyone?

Do you know anything about this?

I would be so grateful for any help at all

She is in Duke University Hosp in Durham, NC

Thank you so much for any help at all