levothyroxine and tachycardia / palpitations

[BaileyCat23]

hi everyone

I’m wondering if anybody on here has any pre existing arrhythmias but also taking levothyroxine? I have recently been told I have Subclinical hypothyroidism (tsh usually higher end or normal or just above normal range)

I have been put on 25mg of levothyroxine but read online this can increase ur heart rate and give you palpitations

I already get palpitations, my resting heart rate is quite high and I have SVT

This has made me nervous to start the levothyroxine as the last thing I want is to increase my heart rate further, or trigger an SVT / palpitations

If anybody has any experience with this I would much appreciate any advise

thank you

[Rosie1066]

Hi, I am on Levothyroxine 50mgs and have been for very many years, I also suffer from Atrial Fibrillation but never had a problem caused by the Levothyroxine. In my case the AF was also long standing ever since I had open heart surgery for a replacement aortic valve fourteen years ago. In my case my heart rate was low and for that I have recently had a pacemaker implanted.

[BaileyCat23 in reply to Rosie1066]

Thank you Rosie, this is reassuring !

[benjijen]

I'm on alternating daily 125/150 per day and gave never had problems with heart rate.

[BaileyCat23 in reply to benjijen]

Thanks Benjijen that is very good to know - do you get any side effects at all on the levothyroxine? X

[benjijen in reply to BaileyCat23]

No side effects and was on them before my heart/joint problems began so I can be sure of that. My only problem was I had a bad bout of flu and put on about 4 stone in as many months before I was put on levothyroxine and never been able to shift it so the sooner you're on the correct dose to avoid that the better. I'd never been overweight before and that's the hardest thing for me to accept.

[Fourwhitesheps]

I am on 100mg and never had any problems for over 25 years. The doctors will check your levels to make sure your on the right amount.

[BaileyCat23 in reply to Fourwhitesheps]

Thank you, this is reassuring to hear xx

[Easternmost]

Hi,

I take 50mg of Levothyroxine daily for an underactive thyroid. I was on this before my meds for SVT began. I now take Bisoprolol and Rivoroxiban as well. I have had one ablation.

I don’t believe that the Levothyroxine impacts the heart rate - I would imagine problems more likely if you didn’t.

How frequent is your SVT and what sort of rate do you suffer?

Best wishes.

[BaileyCat23 in reply to Easternmost]

Thank you, I have SVT less than 5 times a year but when it happens it’s extremely high - between 220-250BMP and I feel quite u well. I take verapamil at the moment for it. How did your ablation go? The cardiologist has suggested this for me as an option

Do you mind me asking your TSH levels before and after taking levothyroxine

[Easternmost in reply to BaileyCat23]

We sound similar! I average 220- 240bpm - triggers seem to be stress, dehydration or bending! Immediately goes super fast. I was ablated in 2020, but had another episode earlier this year, so went back on Bisoprolol. I was disappointed at the time, as it is supposed to be a 95% success rate - however, I now view it that it is still a success by reducing the frequency of them and although I’m not keen on Bisoprolol, I am thankful for the rate control as long as it lasts!

I think the Thyroid does play a part in all this, but am afraid I couldn’t tell you what my levels were/are. My doctor monitors it and I seem to keep within range. Sorry not to be more specific.

I am female, 56 and live in the UK.

Very interesting to find fellow SVT sufferers, especially with the high heart rate. Does it knock your confidence with travelling ? - I haven’t flown since, although I’ve been told I can.

[BaileyCat23 in reply to Easternmost]

Bending over is a trigger for me too! Most of the times I have experienced SVT it has started when bending down / over, sound very similar indeed !!

It absolutely affects my travel, to be honest I just never want to travel these days as I panic so much about going into an SVT and needing an ambulance or something ! It just goes so high 256bpm is my highest recorded and it just makes me feel like I’m going to pass out, it’s so scary !!

How many SVTs would you get before ablation? The thought of ablation also petrifies me lol. I am female 33

I am convinced it’s hormone related whether that be thyroid or any other type of imbalance, hoping the levothyroxine may help but worried it will affect the heart rate adversely too so will have to wait and see!

Thanks for replying it’s good to hear from similar experiences xx

[Easternmost in reply to BaileyCat23]

It’s actually such a comfort to hear from someone with such a similar experience- most people (even some nurses) look horrified when you mention rates at our level! That said consultants never seem phased by it at all.

I think I had it from my twenties and just dismissed it as palpitations. It used to self rectify quickly and my trick was just to lay down and it would stop. When I was 52 it became more frequent and stopped correcting without medical intervention. I was diagnosed with atrial flutter / SVTfollowing two episodes and was ablated at BARTs. I was drug free for 2 years and then had another episode in Feb this year - back on the Bisoprolol twice daily. It’s my choice to stay on the Rivaroxiban (anticoagulant). I have been told that if the episodes start becoming more frequent they will give a ‘touch up ablation’ as it is possible that my heart has healed the scar tissue too well , or that a new electrical pathway has formed.

I really don’t know if the Levothyroxine can cause issues, but I do not think it has affected me negatively.

Feel free to message any time x

[BaileyCat23 in reply to Easternmost]

I agree it is a comfort to hear from someone with such similar experiences ! How did you find the ablation? Were you awake? Same goes with me if ever you want to make contact to chat the door is always open! X

[Easternmost in reply to BaileyCat23]

Yes I was sedated and remember chatting with the nurse, I don’t remember any discomfort and it seemed to be over and done with very quickly, which was amazing as I am a complete coward!!

[Partner20]

Levo can cause symptoms such as palpitations if your dosage is excessive leading you to be overmedicated and experiencing hyperthyroid-type symptoms as a result.You have been put on the lowest starter dosage, obviously due to your current heart issues, and your levels will be checked at regular intervals, 6-8 weeks after starting treatment and at the same interval after any change of dosage until your levels are optimal and stable. Keep a record of your results as you will be able to chart your progress. Unless your tsh goes below range combined with an above-range FT4 you are at no risk of overmedication. However, if you experience hyperthyroid symptoms at any time report these to your GP, although, confusingly, hypo and hyper symptoms can be the same, including palpitations! Make sure you take it correctly, with water only, either an hour before food in the morning or four hours after food at night, and 2-4 hours away from other meds and supplements. If you make sure you get those regular blood tests you will be fine.

[BaileyCat23 in reply to Partner20]

Thank you very useful indeed. I have also read re hypo and hyper symptoms being similar re the palpitations, so very interesting ! I’m hoping starting levothyroxine will help with these symptoms but when reading online, hypo usually results in a slow heart rate but mine has always been quite high despite also having a higher than average TSH, hope it doesn’t go any higher

[Partner20 in reply to BaileyCat23]

It is actually quite common for people with untreated hypothyroidism to have a fast heart rate, breathlessness, high bp and palpitations, which can be confusing. Your levo will not have an instant effect like a painkiller, but will build up slowly in your system, which is why you will be retested within 6-8 weeks. It is highly unlikely that your heart symptoms will worsen as there is little danger of being overmedicated yet, and your test results would show this with a below-range TSH and above-range FT4. It is also important to make sure that your vitamins and minerals such as Vit.D, B12, iron ferritin and folate are at optimal levels, as low levels or deficiencies in these can result in symptoms similar to those of hypothyroidism. Hopefully as you only have a diagnosis of subclinical hypothyroidism, your levels will soon optimise with few dosage adjustments. I assume that your thyroid antibodies have been tested to see whether you have Hashimoto's, the most common cause of hypothyroidism. This will mean your thyroid condition is an autoimmune one, but all forms of hypothyroidism are treated in the same way.

[BaileyCat23 in reply to Partner20]

That is very interesting as most of the online info suggests Subclinical or hypo would make your heart rate lower, so this is really good to hear thank you, I hope in that case the levothyroxine may potentially help with the heart rate issues on my case ! really hoping for optimal TSH levels so Fingers crossed regarding the heart rate once these are at an optimal level.

Yes I was tested for antibodies and they were clear.

Also take multivitamins re the other bits you mentioned

Super helpful info thank you

[Silvertail]

I'm on Levothyroxine but it doesn't give me palpitations or any other problems.

[BaileyCat23 in reply to Silvertail]

Thank you, this is good to know x

[Hidden]

Sorry, all, but just to clarify, I think you'd all be taking thyroxine in mcgs-not mgs!! You'd all be flying to the moon!!

[BaileyCat23 in reply to Hidden]

😂😂 that made me chuckle