I am taking my dog to get heart tested next week and the vets have called today to ask that I make sure my dog is starved the night before.  I was just wondering if it is normal practice to starve them the night before?

I'd be guessing this is a ECG which may need the dog to be sedated hence why you have to starve...
To have a normal holter or a heart exam by stethascope you don't need to starve or at least when
my dogs have been tested for holter/stethascope they've never needed it.

This is what I thought.  To be honost I won't be very happy if he needs to sedate my dog as all I'm expecting is him to use the stethascope to give him a score. 

Hope all goes well, Let us know the outcome. Loislane