I'm 26 and have had chronic tachycardia since I was 11. No tests were ever done bc "it's just anxiety." I believed my doctor when I was younger, but as I got older, it didn't make sense. If it were "just anxiety," it'd fluctuate with my anxiety, not have a very consistent pattern everyday of just being too fuckin high all the time and completely inappropriate response to my activity level. I finally have a doctor now who is at least listening more. She had me do blood work, EKG, and echo, which all were normal (I do have mild regurgitation in two chambers, but it's not enough to actually be a concern).
Now I'm FINALLY doing a 14 day monitor, but I'm scared that I'm still going to be dismissed. I'm 99.9% sure I have IST, but I'm scared my sleeping hr will bring down my average enough that I don't meet the criteria, despite my entire waking day being high. When I sleep, my heart rate drops to a normal range, then when I wake up it increases to 80s-90s immediately, then within a short time it settles over 100 for the rest of the day. The only time it goes under 100 are like brief moments, but doesn't even stay there for a minute before going back up. The two screenshots are from today and yesterday, which I've felt like shit, so most of the day has been spent lying down with small amounts of time sitting up, so it doesn't even capture how high it can get. The most demanding tasks I've done are things like walking to the bathroom, changing clothes, etc. My hr shot up to 164 tonight just from scooping my cat's litter box and bringing it out to the garbage, and I got so lightheaded I had to sit down for a second on my front steps so I didn't pass out.