Will unused heloc effect mortgage app

Evening

So I recently moved mortgage over from td to rbc. They're offering a heloc with 100k available credit

My wife and I plan to purchase real estate in the next year or so my question is will that heloc even if it's unused with a zero balance effect the ratios and mortgage application?

If so is it possible to just cancel it weeks before we do the mortgage application..because I like having access to funds in case emergency.

Thank you