Thyroid UK
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Anyone had slow heart beat and TFT results?


A friend has just been diagnosed with slow heart beat, and SCH.

Consultant said the tft results were not bad enough to have effected the heart.

I wondered if anyone had experience of slow heart and abnormal thyroid, just so friend had something to compare to, and perhaps something to persuade GP to prescribe levo.

Results in this case were: TSH was 8, and T4 was 14 (11-22).

Thanks to folks on this forum I knew we had to push for numbers and printout, otherwise consultant would have led friend to believe nothing was wrong with thyroid.

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Slow heart beat is a clinical symptom of hypthyroidism. I don't know what SCH means.

I am assuming she has been prescribed levothyroxine as her TSH is high with lowish T4?


The cardiovascular signs and symptoms of thyroid disease are some of the most profound and clinically relevant findings that accompany both hyperthyroidism and hypothyroidism. On the basis of the understanding of the cellular mechanisms of thyroid hormone action on the heart and cardiovascular system, it is possible to explain the changes in cardiac output, cardiac contractility, blood pressure, vascular resistance, and rhythm disturbances that result from thyroid dysfunction. The importance of the recognition of the effects of thyroid disease on the heart also derives from the observation that restoration of normal thyroid function most often reverses the abnormal cardiovascular hemodynamics.


Consultant said the tft results were not bad enough to have effected the heart.

TSH was 8, and T4 was 14 (11-22).

The consultant was wrong. And despite TSH over range and Free T4 in range being classified as "sub-clinical", it's an arbitrary definition that has nothing to do with reality. Sub-clinical, in most circumstances, means "without symptoms". But what it really means in the context of underactive thyroid is "doctors are going to ignore symptoms".

You and your friend might be interested in this graph, which shows the TSH distribution in healthy people with no known thyroid disease - read the text on the page as well as study the graph :

You'll notice that 8 is such a high TSH it doesn't even appear on the graph.

The data for the graph came from this paper :

The most interesting part of that paper, in my opinion, is the right hand half of Table 3. It shows the median TSH for different ages groups in each gender, where there is no known thyroid disease.

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Huge thanks. I'll print and read whilst I'm topping up vid D - wonderful day here.

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I have a ridiculously slow heart (under 40bpm a lot of the time) and I have had all sorts of investigations to rule out problems. It was like it when I was on both too low a dose and to high a dose. I run a lot, but otherwise I think it's just me. Makes me a little dizzy sometimes but otherwise I'm kind of used to it now. Freaks GPs out when I haven't seen them before though!


Thanks for your reply mountaingoat83. Can you remember what your TSH and T4 was when your heart was 40 bpm, please?

From what I can gather over last few days, a 40 bpm should result in a pacemaker if thyroxine hasn't boosted it.

NB I'm no expert and have only just started looking at this aspect of hypo symptoms and correlation to bradycardia.


Hi Greenwall, i actually got a blood test result today - tsh is 0.1 so I will be reducing my dose. Heart still pottering about in the high 30s / low 40s though! But have other symptoms of overmedication. I've had several ecgs and an ultrasound and there is nothing structurally wrong. It also goes up a normal amount when I exercise.


Huge thanks for this info. Consultant cardio said you could only have bradycardia if TSH was around 60.


You're welcome. Mine is classed as sinus bradycardia, but given that it has been investigated thoroughly and doesn't generally cause problems it doesn't require treatment - I was scared I would need a pacemaker. If your friend has issues like fainting, feeling very weak, heart rate not increasing when moving from sitting to standing etc that would be a cause for concern. I didn't even know mine was that slow until a doctor told me!


Hi. Yes friend has been told it's sinus bradycardia. GP has repeated ecg for 3 mins; and bloods (ie wouldn't believe hospital results), so any further action delayed for yet another week.

As for change in heart beat when standing, I don't know, but thanks for that as I can suggest friend checks it.

Can I ask if you have episodes of fainting? Apparently friend has had episodes annually, but has seemed normal inbetween. Well apart from excessive sleeping (12 hours); and a couple of mild hypo symptoms. Otherwise very active, so never gave impression of there being a problem.

Docs are saying not to drive, which is a lifestyle changer. However, if pacemaker fitted then friend can drive again.


Sorry for the late reply - no I haven't fainted at all, so the bradycardia is less of a problem for me from that point of view. If I did, I think they would do something about it. But overall it doesn't really affect me. 38 on waking this morning!


Hi. Thanks for your reply. Not worried it took awhile. Friend referred to heart team for long term monitoring. Bloods "normal"....


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