Hello and welcome to HCM.
Thanks for putting your query over here.
Its good you have all the tests negative.Yes,your
tachycardia is because of anxiety which can be managed.
If I was your treating doctor,I would recommend,
-Practicing regular yoga,medication,mind
relaxation techniques and breathing exercises.
-You may visit
Psychologist for
behaviour therapy.
-You need not freak out at your
heart rate.You directly dont have any symptom.If you keep on checking your heart rate fearing why it is high,it leads to more anxiety.Instead engage your mind in some hobby,sports,music that will relax your mind.
-Certain medications like metoprolol are used in anxiety related tachcardia.(prescription drug)
You need to visit physician if you start getting dizziness,headache,sweating.
Hope this information helps.
All the best and thanks.