I joined this forum years ago but not had reason to post for some time but, now I would like some advice please.
Blood test results re Thyroid Function show very low TSH and high (out of range) Free T4 which has been like this for the last few years. I feel best with these levels, I have to say, but GPs at my surgery continually tell me I need to reduce my dose of Levithyroxine (150mcg daily) The more senior GPs accept this more readily, whereas the 'junior' ones don't like it.
Before developing hypothyroidism, I suspect my then 'normal' was at the very extreme of the normal ranges as it was many years before my blood tests suggested hypothyroidism, hence why I feel better when back at the extremes again.
Today, I had a phone call from the GP (trainee) that I've recently seen regarding a different issue (unrelated to this), is concerned because Free T4 is high, TSH low, as usual. When I explained this was how they had run for the last few years and I felt better at these levels, she tried to explain how such a raised FT4 was likely to cause problems such as Atrial Fibrillation in the future. No one has suggested this to me before but that doesn't mean it isn't the case, of course.
Is it documented anywhere that raised FT4 can cause AF, and maybe other health issues? I'd like to get more knowledgeable about this, please, but haven't managed to find anything about this, possibly due to incorrect use of key words to search.
So, just for completeness, here are my results from Dec 2022, 4 April 2023 and 1 July 2023
20 Dec 2022 – 8.30am (after Thyroxine)
TSH level 0.02 miu/L [0.27 - 4.2]
free T4 level 30.3 pmol/L [12.0 - 22.0]
4 April 2023 – 8.30am (Before Thyroxine)
Serum TSH level 0.08 miu/L [0.27 - 4.2]
Serum free T4 level 26.0 pmol/L [10.5 - 22.0]
1 June2023 – 1.30pm – (after Thyroxine)
Serum TSH level 0.05 miu/L [0.27 - 4.2];
Serum free T4 level 27.8 pmol/L [10.5 - 22.0]
I just feel I need a bit more Information and reason to argue the point
Many thanks for any advice and suggestions