Thyroid UK

Heart murmur

Hi all, I finally had an appointment with an endo yesterday, after a few months of feeling less than A1. Main symptoms have been feeling quite up and down with physical and mental tiredness/fatigue; dodgy digestion; and insomnia/anxiety which doesn't seem to be related to anything going on in my life. Whilst examining me, the endo noted that my pulse rate is pretty slow (39), and I apparently have a heart murmur. He sent me off for various blood tests, plus an ultrasound and ECG for my heart, so I'm awaiting the results. Despite saying I feel fatigued, I do a lot of exercise (it often actually makes me feel better), so I'm not too worried about my pulse.

I'm on 75mcg and my last bloods in March showed TSH 0.07 (.27-4.2) and T4 18.1 (12-22), however I don't feel overmedicated. In fact I tried 50/75 for three months over winter to see if it helped with the anxiety but it didn't and I couldn't think straight! I had a low T3 result last year, but the endo has said he wants to see what the deal is with my ticker before checking T3 again.

Just wondered what other people's experiences have been with heart issues, and whether they've needed to raise or lower levo, or neither if unrelated.

Many thanks,


5 Replies

A low heartbeat as well as a low temp are also symptoms of hypothyroidism before being diagnosed.

Athletes usually have very low pulse rates but a heart murmur is different and is right it should be investigated.

A low T3 can cause symptoms particularly if we don't convert levo sufficiently as T3 is the active hormone required in our receptor cells. It makes me wonder if the murmur could be caused by your T3 being too low and your heart cannot pump efficiently? Bearing in mind I'm not the medically qualified in any way. This is a link:


Have just seen this link which may be helpful:

Thyroid hormone is a well-known regulator of cardiovascular function and metabolic rate (1, 2). Hyperthyroid patients display increased metabolic rate and weight loss, despite increased food intake, as well as a profound tachycardia (2). Conversely, hypothyroid patients often suffer from weight gain and bradycardia

Does your Endo needs a refresher course!


Thank you Shaws, I will have a good read of these.

To be fair to him, he was far more open to helping me than I was expecting! We shall see how appointment 2 goes...


I hope it goes fine and that he is amiable to the patient helping herself by researching/reading. Best of luck on next appointment.


Hi A lot of people have a heart murmur ,after tests it often turns lout to be insignificant ie does not matter.

Best wishes,



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