I have a congenital heart defect that makes me susceptible to tachycardia (Wolff-Parkinson-White syndrome). Obviously, I have had it all my life, but it was under control without meds until I became hypo and was started on levothyroxine.
Unfortunately, my PCP was totally unaware that thyroid meds could exacerbate this problem and started me on a dose that was much too high. I had to back off and back off until I was down to 25 mcg, and still the tachy was out of control (10-20 times a day vs. 3-4 times a year before levo). I was finally forced to start taking a beta blocker to control the tachy.
My tachy is episodic...I go from a HR of 60-something to 200+ in a matter of seconds, and it stops just as fast. Episodes can last from seconds to hours. I control these episodes using the Devalvo maneuver.
I think there are a number of triggers...emotion, anxiety, hunger, hormones. However, my tachy does not seem to be triggered in any way by physical exercise...in fact, I am most likely to have it when sitting quietly. Actually, when first on levo, I was having most of my episodes between when I went to bed and when I fell asleep (tricky to fall asleep between a couple of those!).
So, technically, I guess my tachy is not CAUSED by thyroid, but it has most definitely been exacerbated by thyroid. I was overmedicated briefly, and the tachy once again went out of control. I backed off to my previous dose (only 6.5 mcg less!) and have been balanced between tachy and thyroid ever since.
Hope you can pull some useful information out of this. Are you having tachycardia? If so, I'd like to hear your answers to your (very good) questions.
I had it due to my thyroid. (Graves/hyper/goiter). I could hear my heart beating at night (literally). I would get flushed, hot & clamy, but did NOT know what was going on.
When i hit thyroid storm my heart rate was 140 bpm sitting down. I guess the tachycardia did not really bother me because I did not know what it was and assumed it was just how my body was made. I literally ignored it, but was also misdiagnosed with anxiety & depression. Only thing that saved me unfortunately was when I hit the first of two thyroid storms and my goiter became very noticeable. (lineman's neck @ 88 lbs..)
I asked this question because i was trying to find out what's really my cause of tachy.
I have tachy episodes but not tachycardia 24/7.
It used to be once in a while but the last month it was everyday.
Apparently yesterday i realized that i have a hypersensitive heartrhytm where any kind of CNS depressant (like betablockers) makes my heartrate too low...
any kind of CNS stimulant makes my heartrate too high.
1 cup of coffee is drinking 20 in a row.
my own body's adrenalin is also a CNS stimulant,
so whenever i get a little bit stressy, anxious or happilly excited i've been having tachycardic episodes daily.
the peak of a tachycardia usually sends me to 140bpm at rest and that lasts 15 mins.
after 15 mins it usually stays at 100bpm at rest for at least 30 mins.
doctors suggested i am superstressed or having panic attacks,
but because i get high heartrates from excitement or just for "no reason at all" i didn't believe them.
so i guess i'll have to learn to be supercalm mentally,
and hopefully with better eating and living habbits my tachycardic episodes will become very rare events.
if better food, mind and life doesn't fix it then i could always get a pacemaker that does not allow my heartrate to go below 60,
this way i could tolerate betablockers or the new "pure heart rate reduction drug" ivabradine...
but i know that it's better in the long run not to take any kind of drug if you don't have to.
Do you have a diagnosed thyroid condition? Are you taking any thyroid meds?
My tachy is the same...99'9% of the time my heartrate is absolutely normal (or even a bit low now that I'm on the beta-blocker)...every once in a while it goes crazy. It's quite miserable.
My tachy starts and stops like someone flipped a switch. The Valsalva maneuver usually stops it promptly, but if I don't do that, it can go on for hours. Just after starting levo (dose too high), I had it for something like 14 hours and couldn't do a thing to stop it.
Do you have a diagnosed heart arrhythmia?
Thyroid problems can exacerbate known cardiac arrythmias and bring unknown ones to the surface. In people with healthy hearts, high serum T3 (especially) and T4 levels can cause tachy, also. However, people without an underlying arrythmia seem to experience tachy not as episodic, but as a constant elevated HR, but not a super-fast HR.
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