eja - think yourself lucky you did the right thing and went to see your doc after experiencing those symptoms. All to often they are ignored with a fatal result.
The nuclear stress test is a no-brainer. Technetium-90, a gamma emitter, has a half-life of 6 hours, so by the end of the day, it's all gone. CT scans are potentially much more harmful.

It looks like your asthma is well controlled if you can do 17+mph for 40+ miles. What meds do you use?

Good luck.

Artmo, thanks for the good wishes.

I use Advair, twice a day, and I have a Proventil inhaler that I carry for emergency situations. I hardly use the Proventil, however.

I ride a lot on PCH, next to the ocean, I think that the heavier, moist and "salt-rich" air makes it easier for me to breathe.