Hi, first post here. I was diagnosed with IST 3 years ago. I noticed the symptoms after recovering from pneumonia. Had a rate of up to 220 beats when doing minimal things such as showering etc I was breathless and felt exhausted constantly. After many A&E visits I Finally got admitted to the cardiac ward and met my specialist who diagnosed me with IST after a 3 days monitor on ward and some other tests (echo, urine collection, etc) I started on Ivabradine and had a massive improvement which I’m so grateful for. I don’t know anyone else with the condition or anything even similar to it so wanted to reach out here to others. I’m finding it very depressing at the moment but I can’t put my finger on why. Wonder if others living with IST feel the same? Thanks
Living with IST: Hi, first post here. I... - Heart Rhythm Diso...
Living with IST
I have IST too, was diagnosed in May. On Ivabradine too. You are not alone. I was exhausted all the time. I found recently my iron was low, possibly due to meds. Anyway, I was quite miserable with it all. A reduction in my meds helped that. It is frustrating isn't it.
I could go on a lot about it, but also got diagnosed with SVT and long at syndrome. Just to say, you are not alone. Reaching out here helped me recently.
Hi thanks so much for the reply. Its just a relief to read others experiences with this condition! I’ve been doing well but had a bit of a set back with it past two weeks so I think it’s been on my mind a lot more. It’s reallt interesting that you mention having low iron. I’ve had bouts of that too they also said it could be the medication. Do you take supplements? Do you find your IST worsens when your iron is low? I’ve experienced a higher heart rate even on the ivabradine when my iron is low and also my blood pressure drops. It’s a very strange condition. It does help to reach out to others. Good to meet you! 
About a month ago, I had a big flare up, ended up in emergency. Had a mild virus, mine flares up with illness. And I just happened to go to the gp the day before for a "well woman check" and asked for all my bloods cholesterol etc to be checked as felt fine but just as a check. That is where my iron came back super low and the next day flares up. I just had an iron transfusion and yes my blood pressure kept going low too. Saw my cardiologist recently and had a reduction in ivabradine and now for 3 monthly iron checks. He wants me to have injection or infusion if gets low again in future. Two weeks on from infusion, feel much better.
Hi, I have it too... or so the Drs think. Started 2 years ago, maybe touches of it before then, but not as constant. After 3 mos or so of my personal investigation with AliveCor, the Dr suspected it might be IST or a very high atrial SVT that looks like sinus tachycardia. Two more years and he was all but convinced it was a form of IST. Tried beta blockers, calcium channel blockers and ivabradine. Mines a bit weird though and is only triggered by sympathetic stimulation, so it's not all day. Though sympathetic stimulation includes A LOT of things like squatting, bending, eating, drinking, laughing, nervousness, exercise, walking upstairs, pretty much everything. Extreme emotion and exercise had the ability to get it stuck, cycling back and forth endlessly from 90-150 for up to 8 hours which was like running an 8-hour marathon. And the non-stop surges from low rate to high rate were the worst part. So, Dr thinks I could have sinus node reentrant tachycardia in addition to IST. It's very hard to live with, and I agree, not a single person who hasn't experienced it could understand, though I suspect those with POTs and especially the type that causes passing out, have it worse. I'm super tough and an ex-athlete and adrenaline junkie and I find it the absolute most annoying and disruptive thing I have ever experienced.
Right now, mine is pretty well under control with a very low dose beta blocker every 6 hours. I do have some breakthrough but it's not so bad when it's not happening every second of every day. And it doesn't get "stuck" unless I do high-intensity cardio which I'm only just starting to experiment with after virtually not exercising (other than walking) for 6 months per Dr's orders. I'm due to see a new electrophysiologist in 3 days but hopefully, I won't need his advice and the beta blocker will keep working well enough.
I did try ivabradine and it did work but gave me long runs of PVCs a lot so Dr took me off. I'd be willing to take it again though any day if this other stops working because I'd much rather have lots of PVCs than IST.
Are you still depressed now? Or better now that you have a med that's working? It's a very lonely condition that I never talked about to anyone, not even my husband because none of it would make sense and people just think you're a lunatic or an anxiety case or something. I'm glad I can feel a little better. It was like I had forgotten what "normal" felt like and the first day I felt normal, it was amazing!!
Hope you keep feeling better! Feel free to contact me anytime.
Hello! It’s so good to hear from you! Reading your experiences really hit home for me! It’s such a strange condition it’s definitely something I still can’t fully grasp. I do understand about being very active. I’d just turned 30 when this hit me and I went from working 12 hour days, looking after my young son and being very active to having to an ambulance called when I passed out making breakfast when my heart rate hit 210. It’s crazy. I’m very glad to have find the website because I definitely also relate to what you’re saying about not really talking to those close to you, definitely struggling with that right now so that does feed into my depression. Anyway I could go on but it’s definitely helped to read your message! X
Wow, 210 is really high. Hope it doesn't do that anymore! Yep, I was 38 when mine first landed me in the ER. I have 2 kids and you're right, it's been tough. Zapped any and all energy I had out of me. People complain about how tired beta blockers make them, but what's funny is they actually give me way more energy compared to how I used to feel, haha. They even tested me for narcolepsy because I was so worn out every day and having all kinds of sleep disturbances. I tried to tell them it was my heart causing that but no one really listened. Then I just started to doubt myself and that was the worst. I feel better now that I know it's my heart because I thought maybe the new feeling was my normal and I was just complaining about nothing. But nope, once it went away I knew it wasn't my normal and remembered how I used to feel. Sorry for the ramble... and feel free to ramble anytime. I think IST is a fairly rare thing so it's nice to talk to someone who knows!
Not rambling at all. Feel free It’s interesting to hear others experiences with this as like you said it’s rare. Honestly I’ve been feeling very alone in this condition so it’s just nice to know that others can relate. That must have been very scary feeling so tired and not knowing why. I definitely had the same thing. Even simple things left me exhausted. How do you feel now you’re starting to exercise ? Hope you’re having a good day, feel free to contact
Me anytime
Hi, sorry to imp on too. But YES!!!!To the tiredness, they thought I had chronic fatigue or was anxious until I was diagnosed happening in my sleep. Agreed meds made me feel so much better than before. And going from very active to trying to not set it off has been hard. It is improving for me. But it is hard and lonely. I talk a lot with my husband about it. But, with friends if it flipped off for a few seconds and then calmed down. They would say that it was distracting and I would get upset. I was like, no my heart just didn't do what it was meant to and suddenly feel exhausted. Before starting medication I felt like I had run a marathon just having a shower. People really don't understand what it feels like. I have been lucky with my cardiologist, I was crying saying to him that I felt like a psych patient, but he turned around and said no you are actually very ill. Now, that made me so relieved, to give it a name. And I am same as you, it is ok, but flares up for multiple reasons, sitting at the traffic lights with the car vibrating used to set it off. Now it is calming down. But cannot recommend enough what I said about iron. We don't have kids yet, still hoping too in future. Great to hear the same from others, if it gets bad for you do you get the shakes?
Yes!! If my heart rate has gone into the 160-180s I will shake. That’s why I was dismissed by one of my family doctor as having anxiety in the first instance. No tests or checks just anxiety.
Hi all, very interesting reading your posts as it all sounds so familiar to myself especially 2k2d , my ist I think is also stemming from my sympathetic nervous system and also sinus node after a large attack from svt caused damage almost 3 years ago, i had an ablation last year for the svt but still remain with IST which im on slow release bedranol (propanolol) then a fast acting one for when the attack does break through, usually after eating, drinking and working nights. I agree with you all its a difficult condition to talk about to people as they don’t understand it , thanks to today reading these posts I have realised im not alone. All the best to you all.
Hi Kerry I do believe the sinus nodule has a lot to answer for! Have you lived with SVT for a long time? It seems there some overlap along with POTS. They actually thought I had SVR until I started seeing my consultant and he did more specific tests.
Im glad it helped to see the posts. I know what you mean it can be difficult to talk about as it’s so unheard of. Sometimes it’s hard to explain! Wishing you all the best
SVT not R 😂
Hi, ive suffered with IST for 3 years almost, before that what was happening was for years but only every 6 months an svt (they think) caused my heart to go out of sync and my heart would only kick back to sinus rhythm after 2 minutes, 3 years ago it took 30 mins to kick back in and i was at the point where my heart was damaged, I think my sinus node and nervous system was damaged as since that attack the tachycardia started, but only when I have triggers as I mentioned earlier. The meds do help so its a case of plodding on.
I was diagnosed with IST recently. A few weeks before this, my diastolic BP went up to 110. It had always been between 60-75ish. I also had shortness of breath following severe anemia. Now my Hb is back up in the mid-normal range, ferritin is low normal. I am taking 2.5 mg bisoprolol, which has brought my HR down to the 70s. The highest I've seen is 85. If I take the full 5 mg, my heart rate drops to 50. I am not comfortable with that, so I stick with the 2.5 mg.
Unfortunately, I continue to have shortness of breath. If anything, it's gotten worse after starting the beta blocker. My cardiologist thinks the IST caused the shortness of breath, which is a possibility. But now my heart rate is excellent, my diastolic is normal, but I still get short of breath walking even a few steps. I can keep walking through the shortness of breath, and it doesn't seem to get much worse while walking, but it doesn't go away either. It's very disruptive and fatiguing. every few seconds I have to take a deep breath. I am not able to exercis emuch and hell I sometimes have shortness of breath even at rest. Nuclear stress test, echo, ECG, chest x ray were all normal. Only thing that came up was a heart rate that was consistently over 100. My holter picked up a heart rate of 100+ for much of the day, dropping to 50 in my sleep but over 100 most of the time.
I am honestly far more worried about shortness of breath, than the IST because I am not sure if the ISt was even the culprit behind shortness of breath. I've led an active life with IST in the past. Now I am majorly exercise intolerant, fatigued, short of breath with minor exertion. My 80 year old relative has more energy than me and can walk faster than me.
I am feeling very frustrated, and I appreciate being able to speak to others with IST. did any of you guys have shortness of breath to the extent I described? If so, how did it get better..assuming it did.
I also have IST. I was diagnosed a couple years back after I was in hospital for a week with suspected myocarditis after a viral infection. I am only 18 now and it has changed my life dramatically. I used to be a really active person, playing for three netball teams but now I hardly do anything, even just walking is difficult sometimes. I’m always tired and get short of breath too as well as occasional chest pain. I was put on Ivabradine and now have reduced to 2.5mg twice a day. It did really help to reduce my heart rate as it would just shoot up to 170-200 just doing minimal exercise. I had a two week ecg monitor on not long ago and it finally recorded some horrible ectopic beats I have been struggling with recently. It recorded over 6000 palpitations and an episode where my heart suddenly went to 170bpm and felt like the blood was almost short circuiting my heart if that makes sense. Not sure if this has developed due to the medication I have been taking...All my echos have come back structurally normal but I feel like what I struggle with on a day to day basis is not normal- and not sure if there’s something else as well as IST. My blood pressure is also erratic, especially when going from sitting to standing.Was wondering if anyone else gets thumping palpitations with this condition..???
Hiya, I also have IST! I’ve only just seen this post and it’s so reassuring that there’s others out there!
I was diagnosed in April this year after suddenly collapsing at college ( luckily minor injuries is right opposite college) so I went to get checked out after I kept having repeated episodes of lips turning blue, fast HR, feeling out of it and just genuine unwell .They did some bloods and an ecg which showed tachycardia. I felt completely normal that morning and I was about to go to the gym! Anyway I was sent home and told to book an emergency appointment with my GP where I had an ECG and bloods which actually turned out normal other than slightly low calcium.
Following that episode I had two ambulances out in the space of two weeks with similar episodes and spent two weeks in hospital on the cardiac investigations unit. When I was first admitted I had a partial right bundle branch block and tachycardia and was put on a bunch of fluid. They did a load of tests clearing out all the serious stuff and then I was diagnosed with IST. They also saw I had a likely bicuspid valve which isn’t causing any problems.
I’m currently on 5mg ivabradine and 2.5 bisoprolol. To begin with I had terrible side effects mainly sever migraines which made me house bound and I was exhausted. I’ve had a brain MRI just to be on the safe side which I’m awaiting the results for!
However I’m now feeling great I haven’t had a full blown episode in about 2 months ( when in hospital my HR was 150bpm in my sleep one night and brushing my teeth was like doing a marathon 😂) my resting HR now ranges from 45-55bpm I’m actually seeing my GP this week as I feel it’s dropping to the 40s too much and I’ve been getting a tiny bit dizzy.
Exercise is a bit tricky after a light jog my HR can go up to 170bpm but I just listen to my body and do as much as I can!
The whole experience was such a shock to my family and myself as I’m such an active person and it just came on so so suddenly!! I’m grateful that it is well controlled now, my cardiologist thinks I will gradually “grow” out of it ( I’m 18) which is great, just looking forward to the day I wake up and it’s gone 😂
I hope your feeling a lot better since this original post and it’s nice to see other people with the same condition as it is a rare one!
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