I can relate about heart trouble but I haven't had the nuclear test - mine is in the left chamber and they can do Doppler with the ultrasound to get the flow rates. I understand that the nuclear dye is to look at the smaller passages like your coronary arteries.

I've had treadmill + echo which worked ok - I had a moment to recover while I lay down and I lost some of the stress for their picture.

I've had "cycling" echo which was a fiasco. In theory they can take the shot while you are pedaling. But the rig had me flat on my back and the pedal strokes kept me jiggling too much to get a shot. It was intended for people who can't even sit up, I guess. Waste of a whole morning to go downtown and wait and do the test.