do i have IST?

[notsureifihaveist]

Hi,

I'm due to see my cardiologist to find out the results of a 24hr holter monitor this week. I just wish they would hurry up and let me know the results - the doctors seem to be taking this very casually due to my young age and good health (good bloods and ultrasound of the heart).

It all started a month ago when I was sitting at my desk at work and my heart started beating suddenly (i wasn't doing anything stressful either, well not that i was conscious of anyway) - i could feel it pounding in my chest. I was taking an antibiotic for a urinary tract infection, so i thought it may be an allergic reaction and called for an ambulance. It took 10-15 mins to get to me and by then, the paramedics told me my heart rate was normal, around 80BPM.

A week later the same thing happened and i was in hospital overnight and put on beta blockers for 6 days because my heart rate was 140BPM at one point. The metoprolol got my heart rate down to about 55-60BPM which made me feel fatigued and generally just not like myself. I was then dismissed from hospital as the cardiologist thought it may have been related to my urinary infection and my bloods and echo came back with good results.

The same thing happened (although less severely) 3 times over the last month - i've quit work because it may be been due to anxiety (I had a dislike of my job and the severe attacks only seemed to happen at work).

All of this uncertainty is just making me more and more anxious about my condition - I'm a worrier by nature, but have been healthy all of my life (I'm now 23). I keep checking my pulse all the time, it goes from 70-90BPM during the day - I hate feeling like this, it's turning me into a nervous wreck, especially at the times when I don't have something to occupy my mind.

I've also always been intolerant to caffeine, I can't have 2 strong cups of green tea or a coffee or a red bull without getting shaky. I also can't go on the cross trainer at the gym for too long without my heart rate going up significantly, so I've always stuck to things like walking outside or pilates. I always thought this increase in heart rate was because I'm unfit (slim build and fast metabolism but don't exercise much!) but now I'm getting paranoid that I may have IST.

I guess all will be revealed when I see the cardio and get the results from the halter monitor. Will keep you all updated, in the meantime, please post with your thoughts.

Thanks!

[notsureifihaveist]

Hi,
I haven't had this problem since my original post in April last year. Unfortunately I've now had two episodes of tachy over the last month. I told my doctor and he seems to think it's anxiety because my echo/holter monitor/stress tests/blood work was all normal despite a slightly elevated billirubin level but normal liver (on ultrasound and blood test).

I really don't know why this is happening to me again! Maybe I have some kind of food intolerance as it seems to happen after i've eaten or drunk foods with artificial flavouring?

Do you think I should go back to the cardiologist? I'm just so scared. My heart rate has been normal all year but when I have tachy it feels about 150-200BPM and goes back to normal in about 15mins.

[Celeste77]

I have severe bouts of IST and was finally diagnosed after 20 years. The symptoms can vary from one person to the next, but my major symptom is a rapid heart rate at all times when I'm going thru a cycle.
My mother, who also has IST, never had a moment without an rapid rate until she started beta blockers.
The only time my hr goes down during a cycle is when I'm sleeping, and even then, it usually stays around 80. I also have times when I get dizzy, have tingling in my hands and lips, or have shortness of breath on exertion, and I usually feel panicky when my rate goes above 125.
I've never had a real short bout like yours though. Mine usually lasts for days, weeks, at a time and then settles down alittle. My resting heart rate right now is 92. Last night it was 113 even after laying down for a few hours. When walking around, my heart rate can be as high as 160....

Known causes of long lasting IST can be, metabolic problems, dysautonomias, or from the sinus node itself from what I understand. Short bouts can be due to anxiety, dehydration, medications, caffeine, alcohol, exhaustion, etc.  I'm going in for overnight testing sometime next month to see if all my arrhythmia's are being caused by an Pheochromocytoma. If that comes out negative, my cardio has suggested Ivabradine instead of beta blockers if my IST symptoms get unbearable.
In some cases like mine, exercise, fluid and salt increase can help.

Hope you find some answers soon!

[notsureifihaveist]

thanks tc1414, i've been good - except for a bit of a panic attack yesterday, haven't had the full blown sinus tachy since i had the infection/was on anti-biotics and meds so fingers crossed that and anxiety combined caused it and i don't have IST.

does anyone have full blown IST and can share their symptoms?

xx

[tc1414]

hi there. your feelings sound kind of similar to mine right now. i checked myself in to the ER a couple of months ago due to an infection i had in my lungs known as sarcoidosis.  but, while i was in the ER, my heart rate suddenly jumped up to over 150, and the docs started treating me with different meds to get it back down. it did after a few hours, but they kept me overnight in icu for surveilance. the cardio on-hand visited me the next morning and put me on metoprolol, which did the same thing to me--very fatigued, couldn't think straight. i even had some dizzy spells and what seemed like panic attacks along with all of it. i've now weaned off the metoprolol (doc only wanted me on it about a month and a half) and am having instances in which my heart rate will go up to between 100 -- 120bpm. when it's not doing this, it's at 70 -- 80bpm. i had no issues with heart arrythmia or anything prior to being in the ER. i'm pretty convinced that going on the beta-blocker is what is making my heart does this now, which could be your case, too. i'm asking a lot of folks on this and other forums if they've had experience with any kind of "beta-blocker withdrawal". i'm really hoping that's what's going on with me. i'm seeing my cardio in two days to do a holter, too. we'll see!
hope everything levels out for you soon!

[notsureifihaveist]

the cardiologist rang me this morning and said the halter monitor showed normal heart rate even though i thought it was having a panic attack, it didn't get alarmingly high. will be seeing him for a follow up in 2 weeks, so here's hoping it doesn't happen again!

[notsureifihaveist]

thanks for your help - also no history of LQTS. will post when i hear back from the cardio, hopefully soon.

[SillyHeart]

Your heartbeats really don't really sound alarming to me, notsureifihaveist.  Your rates aren't dangerously fast.  Let us know the results of your halter monitor.  I'm sure you'll have more information about what's going on then.

[Sammie4258]

Do you have any history of sudden death in your family?  If you do, ask you doctor about LQTS.  If there is no history of this, then do not worry.  It could be panick attacks.  The 140  is a bit high.  
sammie

[notsureifihaveist]

Thanks for posting, it's hard to say because it;s only been captured once on an EKG (140BPM) but it hasn't been that high since, usually i think around 100-120BPM.

[SillyHeart]

You're reporting a totally normal heart rate for 70-90.  What is your heart rate during the episodes where it feels like it's racing?  Is it actually racing, or are you just perceiving it as so?