# My TSH is 0.08 and FreeT4 upper normal. Never had Atrial Fibrillation yet.



## Want2FeelGood (Sep 17, 2011)

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3508199/

Looks like my three years of Synthroid 200 mcg. a day could increase chances of serial fibrillation.

How important is TSH suppression ? Is it worth the risk of A Fib, and if so, for how many years ?

My TG has been at 0.2 - 0.4 for the past few years.


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## Lovlkn (Dec 20, 2009)

For me personally - when my FT-4 is upper range I feel hyper.

You need to have a Free T-4 and Free T-3 in order to properly dose replacement and also to confirm you are converting your levothyroxine properly.


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## joplin1975 (Jul 21, 2011)

A couple of things:

- Suppression is important. But suppression is defined as a TSH of 0.1-0.5. Ultra-suppression is generally frowned upon because of all the stuff the article mentions. BUT...

-A low TSH doesn't cause afib, an excess of hormones does. So, sure, while you want to consider TSH, a low TSH without frees that are out of range means...a whole lotta nothing.

-If you are really worried, get that free t3 test. See where you are & you could probably get the same results from a lower levo dose and a smidgen of Cytomel.


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## Andros (Aug 26, 2009)

It only matters what your FREE T3 has to say and furthermore, your FREE T4 could be high because it is not converting to the much needed FREE T3.

We can better help if we have current TSH, FREE T3 and FREE T4 results that have been taken on the same blood draw and we also need the ranges for those results.

How active are you?

Just to clarify; too little or too much thyroxine replacement can cause atrial fib and not enough can cause it also. The numbers have to be "just right!"


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## Want2FeelGood (Sep 17, 2011)

This paper relates the risk of atrial fibrillation to the suppressed TSH level: http://www.ncbi.nlm.nih.gov/pubmed/22673318


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## joplin1975 (Jul 21, 2011)

Yeah but...

1) Correlation does not = causation. Of course people with ultra suppressed TSHs are at higher risk for cardiac issues. What's the #1 drug used to treat surgically-induced hypothyroid? Synthroid, a t4 only drug. What's the most common cause of afib in Synthroid takers? High free t4. I've see a number of references to papers & other online resources that correlate low TSH to afib and the only thing that really means, in my opinion, is that doctors need to investigate beyond TSH.

2) Correlation does not mean a guarantee that cardiac damage is inevitable. It does mean you are at higher risk. The questions are: what are you doing to mitigate those risks (hopefully testing both frees)? And, are you comfortable with the "risk management plan" for lack of a better term) your doctor has laid out?

3) As scary as stats can be, what happened Joe or Bob does not mean it will inevitably happen to you. I couldn't tolerate a TSH as low as yours, but does that mean it's absolutely wrong for you? No. There are very few absolutes in medicine. As my husband says, if there were, they'd likely not call it "practicing" medicine.


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