I am on t4/t3 and for about a month now I sometimes have a fast pulse (90-105) after I've taken t3 but sometimes hours after I've taken it eg it woke me up one night pulse was 103 and i felt like i was bouncing in bed and I'd not had a dose of t3 for about 9 hours
Elevated heart rate is scary can anyone help? - Thyroid UK
Elevated heart rate is scary can anyone help?


...as Louise Warville has explained in a very recent post we need more information. Someone will then be able to help.....There is a Pinned Post on the right of this page - Everyone Read This.....
jeans, very unusual. I know that at 2 or 3 a.m. your tsh is at its lowest. I wonder if that would trigger something
like that. I really don't know. When I was running on "low" with my Armour, I would get very hard pounding but not racy in the night. I also find when my blood pressure is low, my heart starts racing to bring it up. This is all personal so may not apply to you at all.
Thanks not much more to tell really I've cut down my dose on dr S orders but pulse still racing sometimes Tsh is suppressed as always on t3, and t4 and t3 are both mid range. I know iron was low and am supplementing as much as poss but can't tolerate it not even the spatone, cortisol is ok I think so am at a loss
Thanks Sandy12 Just before I was first diagnosed I had an irregular heartbeat tests were done but all was ok then when I began on thyroid meds the irregular heartbeat disappeared so it does seem like it is related to t3. I have read about it and it does seem to have that effect on some people I just can't find out if its likely to be dangerous!
Sorry! see below.
I've just come across this question. This is exactly what's happening to me - my heart is racing nine hours after my last t3 dose. If you found out what was causing it I'd love to know more. Hope you sorted it out. x
Hi I have decided from reading about t3 that it does cause rapid heartbeat but no one seems overly concerned. I told dr S shortly before he died and he didn't seem too concerned and I also told my gp who put it down to side effects of the medication and I have to say I don't get it as often now my body must becoming accustomed to it. I just wish we knew more about it!! x