In May 2017 I was diagnosed with Junctional Tachycardia, a form of SVT. Since then I have had episodes of palpitations and a variety of different chest pains. It is very alarming when I get a new type of chest pain, which is sometimes persistent, which is why I have visited A&E to ensure that it is nothing other than a symptom of SVT. I am currently taking beta blockers to help cure it, but they don't seem to be working - the dose is only 2.5mg! However, since taking this medication I have felt more tired and over the last few days I have felt slightly light headed, which dosnen't go away and come back - it's here all the time! Is this a side effect of the beta blockers or another symptom of SVT? Should I have surgery? Increase the dosage? I dont know! Any advice or comments would be greatly appreciated. 
Medications can do that so can SVT how long have you been taking the medications and when did you start getting light-headed I have SVT I would say had but not sure yet had my ablation done a month ago but I hear that it takes like 3 months or more for the heart to heal so most cases you feel worse I still got the same symptoms except for my heart is beating in Rhythm now still feel like I can't breathe most of the time some days I feel great still get short of breath dizzy here and there even when they do a study if it doesn't show up then they can't do nothing I think I may have more I've been on metoprolol for 10 years all the sudden my medicine stopped working cuz my SVT got worse tempted to take my medicine but I'm trying to wait it out cuz if I don't have to take medicine anymore I'd rather go that route some people feel instant relief after an ablation for some people they need one or more cuz as I said if you have more than one SVT it doesn't always show up
Hi Peter. The tiredness and dizziness is most likely a side-effect of your meds rather than an SVT symptom. Tolerance of stuff like betablockers varies from person to person so you might get used to them with a bit more time. But I stopped taking all SVT meds when I had the condition because the increased dosage necessary as time went on to prevent SVT made me feel too unwell most of the time.
It might be worth asking your GP or Cardio whether it would be possible to try alternative meds to see if they are kinder to you.
I had an ablation five years ago that cured my SVT completely. I only wish I had it twenty years earlier. Please ask your GP/Cardio whether you are suitable for an ablation and consider it very carefully if it is an option.
Take care