AF Association

Atrial Fibrillation and Hyperthyroidism

I'd like to ask if anybody has developed AF either by having an overactive thyroid or vice versa, like me which was Amiodarone induced. The reason I ask is my AF over the past 4 months has been all over the place. Anything and I mean anything triggered it (Cold drinks being the main culprit), but there have been so many I have written down, it would challenge any EP worth his salt to determine whether it be Vagal or exercise induced.

I'll be honest it has been an awful 4 months and I got pretty low at one point, but I know it effects us all in the same way, so I'm not looking for sympathy :) What I am looking for however is, has anybody in a similar situation, once their thyroid was under control, did their AF episodes decrease? My episodes over the past couple of months have gone from once a week lasting about 36 hours, to 5 days of AF and 5 days without. This has been pretty consistent and I could almost organise my week around when I would or would not be in AF.

I saw the Endocrinologist last week and my thyroid is staring to behave a little better and I have felt great (Even with the AF). My moods and energy levels are back up there and for the first time in a good while my AF free days have gone over a week. I see my EP in two weeks, so I will discuss this with him and I know I'll probably be in AF some time soon, but I wonder how much of my AF has been caused by thyroiditis and if I can expect longer bouts of being AF free.


6 Replies

My AF started c15 years ago when I was diagnosed with thyrotoxicosis (severe overactive thyroid). The thyroid problem was eventually treated with radioactive iodine which left me with an underactive thyroid requiring thyroxine for life. The AF went away but resumed about 3 years later caused by too high a dose of thyroxine. When the dose of thyroxine was reduced the AF subsided but came back occasionally with increasing regularity until it was every 2-3 weeks accompanied by presyncope (near faint) on converting to NSR. I did not want to go along the route of ablation and I had a pacemaker fitted in March this year to control the presyncope. Although I still have AF it is now bearable


Looks like you had a rough time of it as well Patricia. My thyroid has been treated with Carbimazole 2 x 20mg a day. My last blood test showed my levels to still be high, but coming down. I've also been informed that it could go the other way. I struggled with the thyroid issues far more than I have with AF, but my AF symptoms are not a severe as yours. I did once nearly pass out, but that was during exercise before I knew I had AF and it was that, that prompted me to see a doctor. I would consider an ablation, certainly if my episodes are to carry on like they are, but if they are thyroid related and they do decrease to the amount I had before I may have a re-think.


Jason, I would wait and see what happens with the AF when your thyroid problem is resolved which, in my case, took a long time as the medication I was given did not work and I ended up having to have radioactive iodine to knock out some of the thyroid. If the AF is definitely caused by the thyroid problem then it could very well be that it will be resolved without intervention when your thyroid problem is fixed. If the AF persists after the thyroid problem has been dealt with then you will have to have a rethink but meanwhile I suggest that you 'wait and see'. Good luck!

1 like

Thanks Patricia, I know it's a waiting game at the mo. My AF came before the thyroid issues and it was the AF drugs that damaged it. I've had a scan and the results show it not to be too bad. The carbimazole is working and I guess I'm lucky in that respect, but I've had AF a while now and that's like you say something to think about.


I too took Amiodarone for 3 years and developed extreme hyperthyroid. I am currently being treated with 40mg of Prednisone for the thyroid. I stopped amiodarone and am taking Sotalol 80x2. I have been having bouts of afib about every 2 weeks lasting for 20 hours and then go back into NSR. 2 months into treatment for hyperthyroid and numbers are coming down. Only drawback is that amiodarone lingers in your body for possibly a year. I also take Pradaxa. Like you I am not sure if the AF currently is caused by thyroid or possibly digestive problems caused by thyroid and prednisone.


I asked my EP if the frequency of my episodes were down to my Thyroid issues and he said it may contribute, but he thought if the Flecainide was going to work it would control them. I've now been dropped to 10mg of Carbimazole a day (From the initial dosage of 40mg) and my thyroid is all but under control. My episodes are not as frequent and the two I have had in the past few weeks have only lasted 2 hours each, where as before it was days. My weight, fitness and moods are just about back to where they were, so I would say my increased AF was mainly down to my thyroid issues. The next step is an ablation where hopefully one day I can be medicine free, well for a period of time anyway :)


You may also like...