yep, i have had two scans in two pregnancies at 7 weeks and you will def see a heart beat, my first the eqiptment was older and you could just make out a blob which clearly was flickering (its heart) the onen i had in this pregnancy was much more modern and i couldnt beleive how much better (the other scan was only done in 2009 so its not like it was that long ago). You could see the babies (its twins) very clearly, and both hearts, you could actually see their chests and the hearts inside.
Good luck for tomorrow xxx