Tachycardia followed by Bradycardia

[Candis45]

Thank you for taking the time to read my post any help would be greatly appreciated. I was recently diagnosed with low thyroid and been on Synthroid for about a month and a half. The doctors say my thyroid levels are "normal" but have a a goiter and I am still extremely tired. The biggest problem I have is my tachycardia (rapid heartbeat up to 120) when I stand up, mostly in the morning. I get very dizzy and fatigued. My resting heartbeat sometimes drops as low as 39 and I am not physically active. I feel sick, nauseous, and very very tired. I sleep 10 to 12 hours a night and still feel tired. I have been to a cardiologist and had many test done with every test saying there is nothing wrong. I am a 45 year old female of normal weight.Don't smoke or drink.  I have allot of heart disease in my family. I hope someone has some advice to help me. I am running out of time and money.
Thank you for any comments.

[gypsy_soul]

.I'd be asking for a Tilt Table test and finding out if POTS/Dysautonomia is the cause.

[Not_to_worry]

Hi Candice. I have the same symptoms -tachycardia-bradycardia, as well as hypothyroidism. I 34 yrs old and can hardly get out of bed during day. My heart rate during sleep is 38bpm and during day its 140bpm. I was born with 4 sinus nodes,and was in an incubator for 4 weeks. From what my mother told me the cardiologist gave me meds to slow heart rate down and got rid of the 4th one. eventually got rid of the 3rd remaining sinus node as  I got older. I still can feel my heart fighting to pick which one it wants to use. I guess you can say its an electrical dysfunction going on. Maybe you can ask your cardio about checking for that. I can totally relate to your symptoms and I hope all goes well,hang in there!

[Candis45]

Thank you both so much for your input. I have had a Holter test but it was on a good day and of course everything was "normal". The dizziness, and rapid heartbeat do not happen everyday, sometimes I will have it only in the morning, but it seems lately it has been lasting all day, every day. I drink allot of water even up until bedtime, very thirsty, and take a multivitamin.
I am also having severe muscle spasms, when I try to extend or stretch my muscle locks up hard, very painful and hard to make it stop. This has been happening daily now. From what I read muscle cramps can be from low thyroid, (but this bad?) This makes me afraid to work out. I did try to do some cardio, made me feel terrible.
I do keep it cold in my bedroom but I wear warm p.g.s and socks with a thick blanket.
If this is all from my thyroid, I am not sure how long it will take for the meds to work, last test about a month ago said i was "normal".
Get so frustrated with the word "NORMAL", things are not normal in my body. I hope this new doctor I will be seeing Tues. will have some answers.
Again thank you both for your help i will keep your suggestions in mind.

[is_something_wrong]

Hello.

Most of your problems can be related to the hypothyreoidism, but if thats taken care of now (I hope it is, it can take some time to get it regulated), there are a few more conditions that you could discuss with your doctor.

The tachycardia when you stand up, especially in the morning, is common and usually more a normal variation than a disease. It's usually caused by a slight blood vessel dilation at night (how is the temperature in your bedroom?), and a slight dehydration (also: remember temperature in your bedroom) that can cause low blood pressure, and the body compensates by increasing the heart rate to prevent you from fainting.

It's possible to have a very sensitive ANS that can produce symptoms like bradycardia, tachycardia and even fainting in extreme cases.

A condition you need to rule out (I suppose you have, if you have done a Holter test, 24h EKG) is so-called tachy-brady syndrome, sinus node dysfunction or sick sinus syndrome (three names for one condition). It would normally cause more tachycardia, probably atrial fibrillation and severe bradycardia with fainting. It's treated with a pacemaker and beta blockers.

Tachycardia at 120 will usually not cause dizziness, and my blood pressure theory is possibly correct. Something you could discuss with your doctor. There is also a chance that mental stress and slight anxiety can cause the symptoms you mention (there is a condition called neurocirculatoric asthenia, that is closely connected with other somatoform disorders like cardiac neurosis).

This was just some suggestions. We can't give you any diagnosis because we're not medical doctors. Keep in touch with your cardiologist / physician and good luck! :)

[Jerry_NJ]

The only help I can suggest from what you tell us (...not physically active) is try to work you way up the exercise ladder, start slow but be honest and do it every day.  Suggestion, start with walking on the level and even ground:  shopping mall, street/side-walk that sort of thing.  Then work you distance up (start with at least 1/2 mile each trip), and also your speed trying to reach the ability to walk 15 minute miles for a mile or two.. then go as high as you want, just take it slowly and watch how you feel.  Diet is also important.

The resting HR of 39 is potentially a problem sign, and I'd keep an eye on that. Exercise may raise that, but in most cases exercise lowers resting HR.  If you doctor isn't worried about the RHR of 39, don't let me start you worrying.