I take it. I don't really feel anxious when it happens. I'm 22 and had a normal ECG. I just wish it would stop being so fast.
I'm 22 as well and I think it's natural to be worried about this, even if someone isn't suffering from health anxiety. It's important to try to ground our thoughts in fact though. Some people have an easier time with this, but if you're like me it's going to be a daily struggle with only slight improvements, but it will happen.
I have a congenital heart defect so it is difficult most of the time for me to talk myself out of it, but at the same time it's all about your mentality. Some people with real terminal illnesses manage to live life fully until they pass, whereas others become an anxious pessimistic wreck. When my mom passed away she chose the strong option, which is not unobtainable. Everyone's capable of it.
I just had a massive panic attack a few minutes ago and I started obsessively complaining and worrying to my fiance and father who have had enough of my apparent "selfishness" with this anxiety. At the same time, my dad is very unhealthy, smokes a pack a day, and is under a lot of stress (and has officially diagnosed high blood pressure), and he manages to get up and focus on the good in life instead of the bad.
We are not weak-willed for being inherently anxious, but as my parents have proven, anyone is capable of changing their outlook. Everything in life is a conscious choice. We choose to feel the way we do, and while reality is sometimes unchosen (a sudden onset of fatal illness), the way we cope or deal with it always is consciously chosen. Everyone dies, at some point, sooner or later, today, tomorrow, or 50 years down the road. We will all have to come to terms with it at some point and I think anxiety disorders make us come to terms with the idea of death potentially way before "our time to go".
In this way it is a useful tool. Anxiety disorders allow us to cope with the perceived threat of death much before our time. We have the potential to learn how to change our outlooks, to have respect for life and what it offers (both the good and the bad). Fact is the second we are born, we will never feel 100%. There will always be something that feels "off". Is this feeling based off of a real illness? It might be, but as it stands now all we have to go on is modern medical science, and faith. Faith in yourself, or if you believe in this, faith in a God, faith in doctors.
Everyone's body acts differently. If a fast heart rate is how your's is different, then it is going to happen regardless. There are inexpensive pills to control heart rate. The chances of a young heart attack without (and even with) a congenital (birth) defect is slim. The chances of a less-serious heart problem is slightly higher, but most of these are not serious.
I suggested this to another poster. If I were you I'd look into it. It's called mindfulness. Have faith in it, because that is the only way you will receive any of the benefit. There is no reason to wish that a heart beats slower if it is not a medical problem. ECGs can detect a lot of things, and any abnormality would have been picked up quickly by your doctor. Wishing that it beats slower is essentially accepting that you still think doctors might have missed something.
Again, I am not trying to be overly blunt here, but my own health anxiety is about this ----> close to destroying my family life, so I get kind of passionate about it when someone shares some of the same fears.