Thyroid meds and arrhythmias

Hi,

I have two questions.  I’ve read conflicting information on these points, so I’d like your opinion.

Can Synthroid (levothyroxine) and similar thyroid medications produce PVCs (experienced as “skipped beats”) and chest pain in otherwise healthy hearts, or do they produce these symptoms only in diseased hearts – those with coronary artery disease, for example?

And, in both cases, is it safe to keep taking levothyroxine?

Thanks.

[Michael J. McWilliams, M.D.]

Levothyroxine can cause or increase PVCs.  It can do this in both structurally normal and abnormal hearts.  The question I think you are asking -- why would levothyroxine cause PVCs if it is only correcting for what your body should normal have.  There is not a good answer to that one. The mechanisms for PVCs are not well understood. It is clear that some people have triggers, but that does not always help establish a mechanism.  

If you PVCs are clear associated with synthroid, it might help to run your synthroid dose as low as possible without causing abnormal tests or symptoms.

Does that answer your questions?

[skinflint]

I too take a thyroid pill, levoxyl.  I never had a cardiac problem
but every once in while I feel like I can't catch my breath and I
am sitting down.  It's happened just a few times.  The only
cardiac test I've had was EKG and that was normal.  I'm on
thyroid meds for a few years now 75 mcg once a day. Do I
need a cardiac workup?