I had SVT for maybe 20 years until I had an ablation in 2018. Regarding triggers, sometimes there was nothing, it just happened. When jogging I noticed that if I stopped suddenly, like for traffic, that would set it off. I don’t think I ever had it for longer than an hour, although it sure felt like a long time. To resolve it I tried the valsalva maneuver, sticking my face in cold water and most of the time I just figure out how to breathe and stretch out my chest. You’ll probably have to play around with some options to figure out what works for you. I was never on meds for it which in hindsight would probably have been helpful.