Hi Wendy,
I have both mvp and svt too. I am 37, was diagnosed almost 2 years ago, after being told for 10 years it was anxiety because everytime they ran a holter test nothing would happen and none of the Dr.'s thought a treadmill test was necessary, so I was so thankful when I finally found a Dr. who took me serious and we were finally able to catch it on a monitor. I take Propanolol and it was horrible for the first 3 months. I was very tired, felt weak, and I guess just absorbing the whole entire news that I really did have a heart issue was draining also.
Like Lyl, I take Magnesium and it seems to help a lot. I also have PAC's and PVC's so it helps with them more so than the SVT. I also agree about the sun, I go to a tanning bed about 2 to 3 times a week for 12 minutes each to get some sun, which makes me feel mentally good (weird I know but even my Dr. has noticed how much "happier" I am when I do) I have adrenaline induced svt so the heat outside actually triggers it if I do anything strenuous so that is why I do the tanning bed instead of being outside too much.
Take some time to let your body get used to the medicine. If after a few months it still isn't working, then there are so many other medicines that are out there they can try you on.
I had a hard time being a mom during those few months getting adjusted so I know what your going through, I hope that you find your relief soon. Just don't let it get you down.
Good luck and just hang in there!
Hugs,
Michelle