I have worked on an acute unit not recently but about five years ago.
My experience is that ECT was only considered for a really deep seated depression that had been treated in other ways. I think it was sometimes used where the person was so deeply depressed that they couldn't benefit from cognitive behavioural therapy or the 'talking' treatments either.
One woman sticks in my mind - I saw her for months on the ward, on a section, and was told she had been senior in the civil service, very 'together', but when I saw her she was wringing her hands constantly and shuffling from foot to foot and was tearful nearly all the time. After ECT, she was transformed and I could for the first time see her as the professional woman she had been - she was discharged quite soon.
I know this is not scientific research for you but thought it might be interesting to hear about someone's experience of it. I'm sure there are negative experiences to but on this occasion it certainly worked - I left the ward though so have no idea whether this was a very long term change in this woman. I hope so.
I'm sure it must be a terrifying thing to contemplate though. Is there an advocacy service in your area? Your local MIND may offer this sort of service where someone could come with you to talk to the Dr about it and get all the info you need, to support you along the way.
Good luck, hope things go well for you wahtever happens.