Make sure you get tested for iron-deficiency anaemia. Low iron can cause all sorts of problems with the heart. I developed tachycardia (heart rate went up to 150) and severe chest pain due to low iron. The solution, as far as the doctors were concerned, was beta blockers. Drugs for anxiety and depression got mentioned too, and so did statins because my cholesterol was high. I refused all those things except the beta blockers which I only took when absolutely essential.
I did eventually get a prescription for two months worth of iron supplements. After they ran out I bought them myself and paid for my own testing. It took me nearly two years to get my levels up to optimal. To get them to optimal I also had to go gluten-free because of absorption problems. The better my iron levels got, the fewer problems I had with my heart.
Your TSH at 0.02 is not amazingly low and a Free T4 of 19 is not particularly high. It is possible you have Graves' Disease, but my first suspicion would be a hyper swing of Hashimoto's Thyroiditis (also known as autoimmune hypothyroidism or autoimmune thyroid disease).
For more info on thyroid antibodies :