Well I do believe fans help.. No matter if it is in a slide or not.
But the Fridge should be properly vented either way. Top or side vent the difference is if you side vent you mount the fridge LOWER on the wall so you have to bend over more to get to the bottom shelf/drawers..
Or as my Mother used to say when she would have one of us kids get something low down "You need to be more Stoop-ed" (As I get older and joints don't bend like they used to.. I fully agree with her. She was a wise woman.. I'm still learning how wise).