This is basically a continuation of this
older thread, but with hopefully a more focused title.
To briefly recap, a couple of years ago I had tachycardia (irregular fast heart rate) during my rides. My old doc simply gave me beta blockers (Atenolol), and even at a small dose I had nasty side effects (low blood pressure, low resting heart rate, feeling dizzy, chest pain, inability to get my heart rate above 120 during exercise) - so I gave up on that route.
So then I switched to my current doc and had an EP study/catheter ablation done, with a diagnosis of AVNRT (AV Nodal Reentry Tachycardia) and successful ablation - problem solved. A year later some symptoms came back, but I was still better off than before the ablation, so I did nothing - as this tachycardia was not life threatening.
Now, fast forward to present day. A couple of months ago the tachycardia happened a couple of times even when I wasn't riding - which was a first for me. It was unclear whether this was the original AVNRT recurring or another problem. So a few days ago I went in for another EP study. The good news is that the original AVNRT didn't come back, but the bad news is that I now have an atrial tachycardia. The cardiologist chose not to try to ablate it, as the success rate for my particular condition would have been very low.
So the doctor suggested putting me on Sotalol while I was in the hospital recovering. I reminded him of my previous side effects with Atenolol, and he mentioned that Sotalol is a potassium channel blocker - so I agreed to try. (Now that I am at home doing my research, Sotalol has some beta blocking characteristics also.) My blood pressure and resting heart rate dropped a bit, but not as bad as with the Atenolol. When I'm good enough to ride in a couple of days, I'll know the effect on my riding performance - but to be honest I'm not optimistic.
I plan to talk with my doctor about the following items, but just wanted to hear some experience on the following:
1. Effect of Sotalol on exercise performance
2. Ditching the medication and just living with the tachycardia
3. If I want to give the medication an honest try, how long to stick with it?
4. Effects of the anti-arrhythmic drugs at altitude (6000-9000 ft) for someone normally at sea level