Hypothyroidism and fast heart rate

[LindaTX]

I had been taking .025mg synthroid to shrink a small thyroid nodule. My Dr. recently took me off it. For 3 weeks now I've had a high heart rate of 100-120 bpm upon doing any activity, even light housework. It makes me tired and a little short of breath.  My resting HR is 70. I probably should have my TSH checked.  Can hypothyroidism cause fast heart rate to come on when one is active?

[LindaTX]

Oh, wow...thanks for that info on the tests to ask for!  I only hope my Dr. will comply. I take quite a few meds and I had asked my Dr. 6 mo. ago if I could discontinue the .025 mg synthroid and she said I could try that and see how I felt.  I'm thinking now these 2 incidents of fast heart rate might be connected with stopping the med.  but it's such a small dosage it may not make a difference.  Other than depression,  I don't have any symptoms of hyper.

Thanks also, dgmootry for your comment...I never realized it took that long for the medicine to take effect.  Glad you are doing well with it.  Do you take synthroid?

[Barb135]

Why did your doctor take you off the synthroid?  Rapid heart rate is often a symptom of hyperthyroidism; do you have any other symptoms of hyper, such as weight loss, diarrhea, depression, etc?

You do need to have some blood tests done, but TSH is the least important.  Make sure you get Free T3 and Free T4 along with TSH.  FT3 and FT4 are the actual thyroid hormones and will tell you much more than TSH does.

You should also have thyroid antibodies tested... the tests you need are Thyroid Peroxidase Antibodies (TPOab) and Thyroglobulin Antibodies (TgAB).  You need them both and it wouldn't hurt to get a Thyroid Stimulating Immunoglobulin (TSI).

[dgmootry]

my heart sped up a few times while my meds weren't up wthere they should be, plus I was haveing palpatations , but now I don't have either, my doctor had increased my med about almost 8 weeks ago, it took at least 7 weeks for things to work out. No problem now