Hi twokates,
I was in a similar situation as you - I have a hip injury and could not do the treadmill test.
They will use a drug called Persantine or something similar which 'stresses' the heart (it basicly speeds it up).
I also had to slowly peddle a stationary bicycle for 4 minutes you may or may not have to do this.
The test is easy - you don't even know your heart is beating faster unless you see it on the monitor.
Good luck.