Hi, I don’t have SVT but I do take a beta blocker daily for migraine prevention (propranolol 80mg SR) and I previously had a low resting heart rate, I was concerned a bit too about my HR going too low but I was getting so many severe migraines I was desperate for them to stop.

After 9 months on them my resting HR did come down on them, but no symptoms like dizziness or fainting, so my resting HR is typically in the 40s rather than 50s now. Exercising HR can’t get to the levels it previously did however and this has impacted on exercise performance I think, I don’t have the stamina I did. Anyhow that’s my experience with beta blockers FWIW, my bp is lower normal these days too btw.

Tbh the only thing that I don’t like about my beta blocker is the slight reduction in exercise stamina but I’m being picky really because I can still exercise well enough, and also a little weight gain which could also be my age. I have known people get other side effects with beta blockers though so I think I’m fairly lucky.

Hope this has given you a bit more info anyhow although realise beta blockers are varying types and also everyone is different.