Having read the article I linked to re psychotic disorders and antibodies:
Autoimmunity and psychotic disorders
healthunlocked.com/thyroidu...
Something made me wonder about other issues and I decided to check atrial fibrillation (including tachycardia). And found this summary/review paper - which is very recent:
Autoantibodies in Atrial Fibrillation—State of the Art
Int. J. Mol. Sci. 2023, 24(3), 1852; doi.org/10.3390/ijms24031852
There are several references to T4, thyroid, Graves disease, hyperthyroidism. But what jumped out at me was this:
Li et al. immunized rabbits with peptides from the extracellular loops of both β1-adrenergic receptors and M2-muscarinic receptors to produce both types of antibodies. Antibodies expression triggered sustained sinus, junctional and atrial tachycardias, but not AF. Sustained AF was induced by addition of excessive T4. Interestingly, AF induction was blocked by the neutralization of these antibodies despite continued hyperthyroidism.
Especially the underlined section.
We've seen a considerable number of members reporting they suffer AF. And that this happens the moment their thyroid hormone levels rise. While others seem to have nothing more than an elevated heart rate. Could the reason for this difference lie in presence/absence of these antibodies - at least in some people?
And I'd emphasise that this happens both in Graves disease and other disorder-based hyperthyroidism - as well as over-medication (and I implicitly assume the wrong balance of T4 and T3 with too much of either to constitute a form of over-medication).