Can a slot-in cooker have the hob isolated before being housing into a unit as an eye-level oven?

If you have a heart condition then you are strongly advised to avoid an induction hob! as you will be likely to feel worse. The electromagnetic field is not recommended for people with heart conditions and completely forbidden for anyone that has a pacemaker fitted. With regard to the question, apologies but its poorly worded so difficult to see what you're getting at exactly? If you're asking is a freestanding all in one cooker with both an oven and hob can have the hob part isolated? Then yes in theory it's possible but requires the oven to be taken apart as wiring inside will need to be disconnected. It's a bad idea though and a new separate oven designed specifically for built in housings would be much safer.