Unfortunately I don't have reports from when I was a child. This was in a post soviet country in the early 90s and I doubt those medical records are still obtainable. At the time I was experiencing some kind of reaction causing high fever, hives and swelling everywhere, and inability to move due to bone and joint pain. I can't remember how long it lasted, I think it was weeks. The doctors couldn't figure out what was wrong and thought I was dying, but in one of their tests they did pick up on the tachycardia.

I'm a little disappointed because I am a rather fit and athletic person, so I'd expect my resting heart rate to be lower as we see with other athletic adults! When I exercise it almost immediately goes to the very high 100s, and sometimes to 200 after strenuous exercise, but I don't consider that to be worrying like a high heart rate at rest.

I will be sure to watch out for the signs and the progression you mention. But in terms of seeking care early - I'm not quite sure what good that would do. If I don't need a ventilator yet and just have normal cold or flu like symptoms (which I'd usually stay home for) how would they be able to help? It isn't like there's a cure right? I would be concerned with going to the doctor and being turned away as there's nothing they can do, but in the meantime taking up valuable time and resources from people who may be more severely ill.