I mean, I had a similar experience with the old doctor not being very worried when I had the same symptom. But when I raised that I was worried about having a heart attack and dying he was equally unworried about that "people die, don't worry about it". And yeah a surprising number of athletes also die suddenly from heart conditions, so I'm not sure I find that very reassuring.

In any case, they did diagnose SVT or some variant. But it pretty much went away, it seemed that getting dehydrated and/or alcohol was triggering it for me.

I actually find a smartwatch that monitors my heart rate very reassuring. I have suffered from anxiety in the past and if I think I'm having anxiety symptoms I can glance at my watch and it tells me everything is fine before I start stressing and making it manifest physically.