My Broken Heart – an Explanation of IST

A lot of people have asked me questions about my disorder, because even my nurse friends have never heard of it. One of my aunts recently asked me if there was somewhere on the internet she as someone who doesn’t know much about medicine could go to learn about my heart problem.

Surprisingly, the answer is, not really. The information that is available through a simple google search is primarily from 2003 and before. It is both outdated and flat-out wrong according to more modern research. As a health care professional, I had access to the most current peer-reviewed journals and research, and I still am not quite sure what to tell people about my disorder. The problem is, there aren’t enough people who have it for there to be good, solid research on it. One of the major midwest clinics that specializes in rare disorders did a two-year study on IST that they published. In two years, they saw 9 patients with the disorder and a handful more who qualified but were unsymptomatic.

You see, this disorder has been documented for a very long time, but it is still not well understood. It wasn’t given its current designation until 1979, when it was labeled Inappropriate Sinus Tachycardia (IST). It generally becomes symptomatic in women aged 20-40, and seems more prevalent in women who work in health care.To explain what it is, I’ll have to go into a bit of a lesson about the “normal” rhythms of the heart. Bear with me.

Sinus rhythm is the rhythm most people are in most of the time. It is the “normal” baseline. Sinus rhythm means the atria are firing before the ventricles to efficiently push blood through the system, and that the rate of beating is between 60-100 per minute.

Sinus tachycardia happens when the heart still beats in the right pattern, but the pattern speeds up. 110 beats per minute, 130 beats per minute, 140 beats per minute. This can push into another rhythm known as supraventricular tachycardia or SVT, which basically means everything above the ventricle can’t beat fast enough to keep up. The heart can beat as fast as 150 to over 200 beats a minute in this rhythm.

Wait a minute… sinus tachycardia can be normal though, right? Correct! Sinus tachycardia is perfectly normal in certain situations. Like when you exercise heavily. Or when you have an adrenaline rush in a situation of danger.

The trouble with IST is that sinus tachycardia happens when it is NOT normal (when it is inappropriate). When sleeping, sitting quietly in a chair, standing up, walking slowly to the bathroom, driving a car, playing a video game, reading a book, watching TV… you get the idea.

IST is characterized by an elevated heart rate all or most of the time, with spikes of the heart rate well over the “normal” range during very mild exertion, very mild stress, or even just being irritated by some dumb kid on the internet. The elevations in heart rate are prolonged and difficult to control with medications. They lead to severe chest pain, nausea, dizziness, lightheadedness, syncope (passing out), and palpitations (you can feel your heart beating forcefully as if it’s trying to punch its way out of your chest, or maybe doing some flip-flops for fun in there).

Consider that the “target” heart rate for an average person doing a 20 minute exercise routine for heart health is somewhere in the 120-130 range. Then consider that folks with IST have a heart rate in that range or higher for hours and hours a day. Even when they are just sitting in a chair doing nothing. It takes an enormous amount of energy to run the heart that fast, and leaves you feeling fatigued, drug out, and emotional.

IST is not caused by anxiety (it was ruled out), thyroid imbalance (also ruled out), or any other hormonal or emotional problem. I’ve had six months of extensive testing, some of it invasive, and all of it difficult to endure. My cardiologist says this disorder cannot be faked and that all other possible causes have been ruled out in my case. My endocrinologist and sleep pathologist and general practitioner didn’t know what it was until I explained it to them. Yeah, it’s really that rare.

The current research and guidelines on IST say that there are three treatment options.

1) A drug class called beta blockers – these slow the heart. They also cause severe side effects in many people, including low blood pressure, passing out from low blood pressure, severe depression, and in men, impotence. My doctor has tried several of these, including metoprolol, inderal, and bisoprolol. The first two caused depression and fatigue so severe I stopped caring for my own needs. For a couple weeks at a time while trying to adjust to the meds, I rarely showered, missed 1-2 meals a day… even brushing my teeth was just too much work. I became suicidal, but fortunately didn’t have the energy to act on those thoughts. Bisoprolol, so far, is only causing low blood pressure and more dizziness, to the point that it is no longer safe for me to drive a car.

2) Calcium channel blockers – these also slow the heart by working on one of the molecular pathways that allow electrical signals to flow smoothly and quickly along the heart. They have been shown to be effective in a small percentage of people with IST, and they come with a host of side effects of their own.We tried this one, too. Cardizem caused me severe and continuous chest pain. For about a week, I felt like an elephant was sitting on my chest. It was hard to breathe, and I couldn’t even walk to the bathroom without assistance toward the end.

3) Surgery called ablation for cases that are very severe and which cannot be controlled with medication. The surgery was once thought to be a complete cure, although symptoms persisted in many people despite having a clinically measurable lower heart rate. The ablation surgery carries risks of damage to the nerves that control the diaphragm (ie breathing), perforation of the heart, inadequate destruction of the electrical initiation cells (SA node) of the heart resulting in a need to repeat the ablation (sometimes over and over again), over destruction of these cells resulting in too low a heart rate and the need for a pacemaker. Further, the SA node can grow back, requiring the surgery to be repeated in 3-6 months, even if it looked completely successful. The surgery also carries the risks of death, brain damage, stroke, and further disability. The risks are considered moderate for most people, but surgeons hesitate to place a pacemaker in someone my age. Pacemakers have risks of their own, including massive infection, dysfunction of the machine, frequent need to monitor and recalibrate the machine, and the need to replace the machine every 5-7 years. My doctor has talked about this as an option for me. He thinks it might help. The risks and long-term complications (like a pacemaker) have to be weighed against my daily life without the surgery, though, and the only person qualified to make that decision is me.

IST is not life-threatening. It is not going to shorten my lifespan. Very few people who get IST progress to any sort of heart damage even after years of elevated heart rates. My arteries are clear. My muscle works fine.

Knowing that, knowing that I will not die from this disorder no matter how much it changes my life, makes facing the risks of repeated surgeries and implanted devices seem unwise to me. The truth is I am here today with my husband and my son. I can still type, read, write, sing (if a bit breathlessly), cook a meal (if I pace myself), and enjoy spending time with my guys.

Yesterday, I was playing an online game and a 15 year old kid said something to me that kind of ticked me off. Not “blow a gasket” pissed off. Just sort of annoyed. I could barely speak for the palpitations. My heart rate was over 140. My hands were shaking so bad that I couldn’t type the reply my brain was cooking up. I am not a docile person. My wit is sharp and my tongue has been known to be even sharper. I turned off the computer and sat there staring at the screen. I could not walk away, for fear of falling on my face. It took over an hour for me to start feeling “normal” again enough to get up and walk around.

Life with IST isn’t easy. I could waste my energy railing against how it isn’t fair (it isn’t), or how I wish it would just go away (I do). I could just follow through with one of those suicide plans I thought up while on the depression-inducing beta blockers.

But I’m not a whiner. Or a wisher. Or a quitter. I’m just me. Fast heart and all.

UPDATE: So many of you have expressed thanks for this post and asked after me over the years since I wrote it that I felt an update was in order. You can find more information about how I’m doing now (2013) here.

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75 Responses to My Broken Heart – an Explanation of IST

  1. tambo says:

    {{huggs}} I still wish I could do more to help.

  2. Arizela says:

    You already do. 🙂

  3. barb says:

    hugs and prayers to you. Wish I was still closer to you and could hug you in person!

    xoxo
    barb

  4. arizela says:

    Thanks Barb! Where’d you go?

  5. Jane says:

    My prayers are with you. I just got diagnosed with IST myself and am now on Cradizem which makes me really tired all the time. We just have to survive this!

  6. arizela says:

    I hope that the Cardizem works for you. I’m having better luck with the bisoprolol but am severely fatigued and still have episodes frequently.

  7. Deb says:

    Currently I going through the process of trying drugs. Dr. is starting to talk about ablasion. Do you know if you can get disability if you choose not to have surgery?

  8. arizela says:

    Hi, Deb.

    I’ve been told that since surgery is a controversial treatment for this condition, often resulting in unimproved symptoms and requiring frequent repetition, it is entirely at the patient’s discretion. I suggest talking to a disability attorney if you want to know more. Also, please be sure your doctor rules out EVERY other possible cause of your tachycardia. IST is VERY rare and other conditions, including Postural Orthostatic Tachycardia Syndrome and others are sometimes misdiagnosed as IST, and some of these get worse with ablation rather than better. I highly recommend getting a second opinion prior to considering cardiac surgery, as once your sinus node is ablated, you cannot undo the change.

    Ari

  9. Thomas says:

    Hello Arizela,

    I am a 39 year old male and I have had this same problem of IST for almost 2 years now. I know how much this problem sucks. The worst part is that doctors can’t tell us where the problem stems from. Also, some family and friends do not understand this problem at all no matter how well you explain it to them. They just think it must be anxiety or something like that. It can be very frustrating!

    I take metoprolol and it seems to work for me pretty well. Although it does make me drowsy and lazy and I have gained about 30 pounds since I started it. For lack of exercise and for the fact it slows down my metabolism. I wish this problem would just go away but I don’t think it will. It makes me very depressed. My life style has changed. I no longer can play basketball without my heart skyrocketing, even with beta blockers. After I play my heart rate is close to 100 for about 12 hours even resting. Makes me anxious felling, depressed, tired, and angry.

    You would think in this day and age that doctors could tell us more. But there is limited information out there. I have spent many, many hours doing my own research and have came up with a few thoughts I would like to share.

    1) Have you ever looked into P.O.T.S. Postural Orthostatic Tachycardia Syndrome, or Dysautonomia?? I keep thinking that this problem has something to do with our autonomic nervous system somehow and it is not regulating our systems right.

    2) Another idea is that our hearts are sensitive to adrenaline?

    3) There is one last theory of mine. Before 2 years ago I was fine, without IST. I had gotten really sick with flu like symptoms. I never been so sick before in my life. Fever, vomiting ect…. I never recovered form feeling normal for about 3 months. That’s when I first had my heart problem. I was admitted to the emergency room one evening and spent the night there where they had to give me Advin to calm me and my heart down. Shortly after that and some tests were done I was diagnosed with IST.
    I had read in a few places online in my research that perhaps a virus plays a role with this problem? Or some sort of trauma to the body like being really sick. Maybe the virus disrupts the nervous system.
    I have also heard of women who get IST after being pregnant and having their baby.
    Maybe this is a shock to some people nervous systems and it can no longer regulate the body correctly.

    These are partially things that I have read and gathered on the internet and also my own theories about my problem. As there is little doctors can tell us I have had to do my own research.

    It would be interesting to hear your thoughts and your own story of how your IST became to be.

    Hope to hear back from you.
    Keep smiling (it’s all we can do 🙂
    Thomas

  10. Phyllis, Georgia says:

    I was just diagnosed with this yesterday and you really helped me understand. I don’t know yet if the meds will effect me or not. Hugs

  11. arizela says:

    Phyllis,

    I’m sorry to hear that you’re having this trouble, too, but glad my story could help you understand the condition a little better.

    Ari

  12. Jessica says:

    Thank you for this information… this has been really helpful for me. I was diagnosed about a year ago with IST and thankfully have been well controlled on Inderal. I had been experiencing symptoms for years and being young everyone just thought I was looking for attention. I’m just glad I have an answer. It seems like you are very knowledgeable about this. I have been getting mixed answers about if it is safe to get pregnant with IST. What is your opinion?

  13. arizela says:

    I would hesitate to offer advice or an opinion on that one, Jessica. Your best bet would be to contact a high risk obstetrician and discuss your condition with him or her. Good luck!

  14. Tegan says:

    hi arizela,
    i am very curious about this disease, and how it affects your every day life. I know you said you get breathless alot, but could i presume things like exercise are out?
    i was recently diagnosed with it, but my doctor didn’t really elaborate about how it might affect my every day life. It would help alot if you could explain 🙂

  15. arizela says:

    Hi, Tegan.

    IST is one of those conditions that affects people differently based on how severe it is. For me, personally, it depends on the day. Some days I feel better than others. Some days I can get some light exercise in without my heart rate spiking over 150 (exercising with your heart rate elevated above that threshold for long periods of time can lead to sudden cardiac death). Other days, it’s 150 if I get up and walk 10ft to the bathroom. It causes a lot of fatigue, and being tired makes it much worse. Part of the difficulty in treating this disorder is that everyone who suffers from it seems to have their own responses to it and to the agents used to treat it. Some folks with IST live relatively normal lives just with a medication. Others continue to have problems despite trying all of the treatment options currently available. For some, it is a minor nuisances, for others, a disabling condition. I personally had to give up my career as a nurse after failing to tolerate all of the conventional treatments for IST. I “manage” my condition through my lifestyle – avoiding stressful situations, keeping a relatively low-key life when it comes to physical exertion (though I do get some exercise in the form of a recumbent bike), having my husband or son accompany me on public ventures (grocery store, restaurants, library) in case I pass out, and passing off the day to day activities that cause my heart rate to accelerate to my very supportive family.

    I hope that your IST is mild and easily controlled. Take care.

  16. nicole says:

    I have this condition as well. Can you email me? It’s just nice to know that there are other people out there who know what it feels like.

  17. Amanda says:

    I suffer from the same thing. Had it for over a year and did the ablation. Which was a success but my heart still jumps at times to 183 bpm. I can’t exercise cuz it hits that 183 range and feel like I’m past out. Which sucks. I can just walk and that’s the only excrises I can really do. And I used to work out everyday and I’m only 22 yrs old. Sucks having it but I live through it and doesn’t stop me from trying to work out. At least I try and deal with the fatigue and dizziness.

  18. Jess says:

    This sounds similar to what I’ve experienced the last few years of my life (I’m 28 now). I was just recently diagnosed with Ehler’s-Danlos Syndrome so I had just assumed from my readings on my condition that I had POTS. Your article gave me something very interesting to look at. Do you know much about the difference between POTS and IST?

  19. arizela says:

    IST is defined as sinus tachycardia in the absence of any other explanation, whereas POTS is sinus tachycardia that occurs because of body position – it doesn’t happen when you’re laying flat but does happen when sitting up, standing, or walking. POTS is also worse when you aren’t using your leg muscles (ie just standing still) because with POTS your body relies heavily on the skeletal muscles to pump blood back up to the heart and if those muscles aren’t moving, the blood tends to pool in the lower body.

    In my case, I have a combination of the two. I was originally not even tested for POTS because I do have tachycardia when lying down, but mine gets much worse when I am upright and still.

  20. Kurt says:

    This is very informative. I’m 55 and was diagnosed with mitral valve prolapse when I turned 21, and was put on propranolol for chest pains, Quinaglute added shortly after that. Those worked well for a number of years, then it was like I became immune to my medicine. Chest pain city became my life. The cardiac centers, several, said I was already on the medicine they would prescribe for me, and told me to see a psychiatrist. I felt insulted, but ended up with a psychiatrist who had been a cardiologist. This was 25 years ago. At time, this cardiologist-turned-psychicatrist diagnosed me as having not just mitral valve prolapse, but ‘anxiety’ as well, put me on xanax, with doxepin for my insomnia. He told me that “most heart doctors won’t look past the heart”, and explained that my ‘fight or flight’ mechanism was out of order, and as in following visits with him, he diagnosis for me became ‘panic disorder’. He told me that my excess adrenaline was aggravating my mitral valve, and why the benzodiazapines, and that I would probably find that I wouldn’t need to even take the ‘heart medicines’ (inderal/propranolol and quinaglute). He informed me that if I was concerned about the addictiveness of xanax, I should look at it like a diabetic who needs insulin, that I need xanax, and will need to take it for life. I accepted that, got on that program and was able to function and work and live again. He was a fine doctor to me for 17 yrs till he retired, later passing away. He had referred me to another psychiatrist who treated me similarly for several years, same medicines, but slightly higher xanax, 7 .5 tabs daily, higher due to more at bedtime so I might sleep (Doxepin helped some, but Dr. suggested raising xanax slightly more. That worked. I lost the ability to see that Dr. and have ended up with new Drs (MD, but not psychiatrist) who say that was ‘old thinking’ and we’re the ‘new thinking’, cut my xanax down from 7 per day to 7 per month!… and I’m having an awful time. I had horrible withdrawals, yes. Another (Mental Health practitioner) prescribed me to have 4 per day, which helped. But to get on to the topic of this thread, IST, I have developed high blood pressure, was put on lysinopril for that, also propranol again, high cholesterol so taking symvastatin, and though I do have some alprazolam for panic attacks, I take less of that now, actually none lately exept if a panic attack, and doxepin for insomnia, just terrible insomnia. Sometimes I can’t sleep for days, though I try… BUT FAST PULSE, seems it’s getting worse just this past year… My blood pressure has come down, but at rest my pulse is almost always over 90, and often over 100, 105, was 123 one time at rest lying in bed reading, my heart pounding hard! I know panic attacks, I know irregular beats, but this is rather new for me, Fast Heartbeat At Rest. I have irregular heartbeats at times, but this FAST PULSE, I didn’t know it had a name or anything, till I just came across this info today about Inappropriate Sinus Tachycardia (IST). I have saved some of this info to learn more about this. Maybe this is what I am having problems with? IST? No doctors have ever mentioned this IST term to me before, but probably because my heartbeat used to be slower than recently. Thank you for sharing your story and hopefully it might provide some answers in my case. I’m wondering, does it sound like I have IST, perhaps, or are the pulse rates I mentioned not high enough at rest? Thanks for the helpful info.

  21. Beckie says:

    I loved reading this. My doctor seems to have me as his project, has specialist after specialist involved, but they all draw blanks. I was finally diagnosed with IST and beta blockers have helped. I am 21 and otherwise healthy, and I feel like no-one is ever going to understand except IST sufferers!

    (Even my mum thinks I’m ‘overreacting, its probably due to anxiety’)

  22. arizela says:

    One of the most helpful things my first cardiologist said to me was that IST cannot be faked and it cannot be ‘just anxiety’ because the tests rule both of those out before the diagnosis is made. That said, stress and anxiety can worsen the symptoms because they trigger the release of hormones (including adrenaline) that cause the heart rate to elevate even more. With IST, that elevation is sometimes exaggerated as well, so what might bump a ‘normal’ heart rate up 10 beats a minute for a couple of minutes, in an IST sufferer could cause a pronounced upswing of 50 more more beats per minute that takes much longer to return to the resting range. It’s all chemical and electrical, but the underlying condition is not caused by anxiety. Just because you look healthy doesn’t mean that your body works as intended.

  23. Megan S says:

    Hey. Im 17 and was just diagnosised with IST. And was not really understanding what I even had. This really helped me. Thanks!

  24. Kurt says:

    Thanks so much for your sharing your story, but also your helpful replies to comments is certainly appreciated, as you can see in the comments section, but I’m sure you have helped many who have not commented as well. I think you are very right about stress and anxiety worsening things, adrenaline-wise. I’m trying to see what I can do to de-stress some things in my life, and also try to alleviate some anxiety-related things, with mixed results. Each day is different, though, gain some ground on some days, but not so much, or lose some ground on others…but I think what helps is to keep trying, and to try different things, try to find some positive people to share things with, uplifting fellowship. Sometimes that’s hard though, and it’s easy to get into a depressed slump. I’m about to try journaling again, which I’ve heard can help get one’s ‘difficult thoughts’ out, and onto paper, and somehow disarm some of that negative tension from being ‘right there’ in one’s thoughts to stress out the day, such as to ‘slow things down’ (adrenaline, and pulse, etc.). Hopefully that can help with insomnia too, of which sleep is so important for health. Thanks so much, Arizela, and to all who have shared.

  25. Amy says:

    Hi I have just been diagnosed with IST. My cardiologist has prescribed me Ivabradine, just wondered if anyone has tried this. It’s meant to be a lot better than beta blockers as works directly on the heart rate and doesn’t have the side effects like low bp.

  26. Aly says:

    Other than my one acquaintance who has POTS I really can’t discuss how dysautonomia affects my life. Sometimes I get the impression from other people that they think I’m merely lazy or exaggerating things. To hear that a lot of my issues are shared by other people out there is reassuring and gives me hope.

    I’m 22 and I was diagnosed with IST about two years ago after being hospitalized for an anxiety attack. They discovered it later during a follow up appointment with a cardiologist for an unusual heart rhythm. I’ve been on and off several different medications since then. We’ve tried Verapamil which was nearly useless It was the same for Acebutolol. Metoprolol was great until I started developing asthma-like symptoms. Atenolol is the one I’m currently on, and it has it’s laundry list of side effects, but it seems to be the most stable right now.

    Most days I’m so tired even with the medication I can’t do very much. I find exercise very difficult, especially here in Texas where summer weather is regularly over 100 degrees. And the medications make me pretty susceptible to heat exhaustion. Working a regular 9-5 is difficult, especially with my unpredictable symptoms, so I haven’t had a regular work in months. I’m trying to go back to college soon so I can earn a decent living in a job where I don’t have to be on my feet 24/7.

    I really would like some sense of normality back. In some ways I feel like my ability to cope has gotten worse since I started the beta blockers. So I’m really hoping to talk to my cardiologist again later this year. I would love if there was some other solution out there. We agree that ablation is out of the question. The only suggestion he has right now is a ‘nerve block’ which he says he witnessed successfully used on some tachycardic patients in medical school. The downside is he doesn’t know any doctors at that hospital who can do the procedure, so he’s going to have to do more research.

    Anyway, I’m sorry for going on the long rant. I just wanted to relate my own experiences and say thank you for sharing yours!

  27. Sally Little says:

    Thanks for sharing your story. I also have IST and find life a struggle some days. I get so tired doing the smallest of things. My heart specialist has me on a drug called Coralan but it’s not doing its job, so she has just increased the dosage. Let’s hope some clever person comes up with something to help us all get back to a slower beat soon!

  28. Lauren says:

    Hi,
    I’ve had IST for 3 years now and it’s been very difficult. I’ve been hospitalized twice for it after I fainted due to high heart rates. I’ve been on bisoprolol, diltiazem, and digoxin. I was recently on both bisoprolol and diltiazem, but got taken off of bisoprolol after my cardiologist found my holter monitors were showing I had an irregular rhythm altogether. My next option is ablation, but my electrophysiologist is hesitant because he doesn’t want me to end up with a pacemaker (I’m 21). He has mentioned Ivabradine to me, but says it isn’t available to patients in Canada yet. I’m just wondering if anyone has been on it before and how it has affected them? Thanks!

  29. Arizela says:

    Hi, Lauren.

    I haven’t used that medication myself. I do, however, strongly recommend a second opinion and a tilt table study prior to an ablation, as Postural Orthostatic Tachycardia can often be misdiagnosed as IST and is actually made worse by ablation.

    Good Luck!

  30. Kendra says:

    I too have IST. Being only 23 when I was diagnosed kind of scared me because even my electrophysiologist kind of just didn’t have all the answers I wanted. I was misdiagnosed with SVT and actually went in for the ablation, that is how they found out it was truly IST. I work training the intelectually disabled individuals to try and maintain good basic self sufficient life skills and some days are an extreme challenge for me when it comes to the total care individuals and stress from deadlines or coworkers. I had the tilt table tests stress tests ekg electrocardiogram and an event monitor for a month, and am currently on 100mg of a beta blocker daily and I still have some severe symptoms now and then.

  31. maria says:

    @Thomas

    I have read about and know other whom their IST presented itself after a bad illness my IST got extremely bad after a wretched stomach bug. It went from not needing medication to needing it.
    I think this is common, I also feel like my IST goes into “remission” of sorts. I can go weeks without symptoms and then some days I cannot even walk up one flight of stairs.

  32. Amanda says:

    I also have IST was diagnosis when I was 21 and now I’m 24. I had the ablation done twice, first time seem like worked for a few days then came right back and the second one so do any better. I’m on inderal and few other to rise my heart rate cuz inderal lowers it and also on depression meds cuz of the side affect to inderal. I feel fine on the meds except when the weather is hot or when I’m sick. I feel 10 worse when it’s hot or ill. There is one other surgery that can be done to help. My doc is the best in LA and seen many of these cases. But the surgery is more intense that require open heart. It’s basically a last resort thing if you can’t deal with it. But I rather deal with iST and hope for it to go away on its own then having open heart.

  33. Valencia says:

    I am very happy to have found your website; I was diagnosed with IST Dec. 2012. Getting to a diagnosis was a frustrating process to say the least. Despite the fact that the symptoms were making me extremely ill, doctors kept telling me it was stress or anxiety. I am a 41 years old woman who was very physically fit, eat a very healthy diet, and my cholesterol has always been great. So needless to say it was a very emotional thing for me to have gotten sick and diagnosed with some rare heart condition (along with moderate heart failure). Thank you for sharing your story and hopefully I will find more resources and maybe a support group.

  34. Kaitlin says:

    I am a 23 year old female and have been dealing with IST for over two years. Symptoms started about 6 months after a very bad case of mononucleosis. It was a very long road to diagnosis, and I am currently on 50mg of atenolol daily. I struggle with the side effects of atenolol- very low blood pressure causing fatigue, and I’m always cold. For the most part, symptoms have improved, but laying down this evening and feeling my heart race is just so frustrating. I recently started working out and worry about how fast my heart rate can safely be. I also have had lots of gastrointestinal issues lately, unsure if this is a medication side effect or an autoimmune issue.

    Before my diagnosis, it was a scary thing having a racing heart for seemingly no reason. My doctor has said an invasive procedure probably isn’t the best option for me becauae medicaion controls most of my symptoms. I would have to agree, and knowing surgery is not a sure fix leads me away from it.

    It’s so frustrating because sometimes I have episodes that completely debilitate me. It’s hard to describe and hard for those around me to understand. I become completely fatigued accompanied by an elevated heart rate.

    My doctor has said that sometimes patients “outgrow” IST. Has anyone experienced this? I’m also curious about any medical research studies about this.

  35. Jan says:

    I found it interesting that some folks say this condition started after a viral type event. I too had a viral (atypical) pneumonia about 7 years ago and have IST symptoms since. It idid not get diagnosed though for at least three years later. One cardiologist said, eat salt, one said if I was his wife he would have me loose 10 lbs and go for a walk daily. I have had no one explain this condition. Your blog is helpful . Thank you so much
    By the way beta blockers did not help, and reduced my ability to do any “walking” so I just cope, and try to explain to friends who go for walks with me why my heart is 150 plus and they are at maybe 95. Oh well, someday they may know more, but with so few of us out there, the studies and monies are not being put in to this condition.

  36. Elaine says:

    Well were do i begin i am 24 yrs old and have been diagnosed with Ist after i got realy sick and was in the hospital for a week with a heart rate between 200-225.This condition is so difficult to live with for a young adult.. i have seen two electrophysiologist they say the same therez isnt much they can do i had an ablation with no benefits. I have a 3yr old son which i cant raise the way i would like because of my condition i really have no family support i dnt even really like telling people bc they look at u weird wen u say u have a heart condition at 24. Im just so tired of worring abt my heart rate rate its emotionally exausting. I feel disabled ppl think im jst lazy.. i wana b normal i cant even excercise.

  37. Elaine says:

    Does anyone know the difference between ist and pots? Does the condition ever improve is there anything i should be doing to help it?

  38. Arizela says:

    Elaine – the difference between IST and POTS is that the cause of the elevated heart rate is know in POTS.

    While we don’t know what causes POTS, we do know that the heart rate goes up because the body is trying to compensate for a change in blood pressure. Sometimes the increased heart rate allows the blood pressure to continue to be normal or even slightly high, but if the heart rate were to stay steady, our blood pressures would drop and we would pass out. Treatments for POTS include medications that increase the blood volume, high-salt diets, and reconditioning exercises of the lower body (while lying flat, to keep the heart from spazzing out).

    No one understands what makes the heart race in IST. Treatments for it are geared toward managing symptoms, but many of the medications cause people worse problems than the IST itself, as I discussed above.

    Sometimes, IST gets better. Sometimes POTS gets better. Unfortunately, full recovery from IST is rare. POTS sufferers recover more often, though they can continue to have symptoms anytime they get dehydrated or over-stressed throughout their lifespans.

  39. Kourtney says:

    I was diagnosed with IST yesterday after years of being told i had SVT. All of the unknowns were really the only thing that had me worried but this article made me feel so much better. My resting heart rate is between 100-105 and my average heart on a normal day is 150-178. This has been the norm for 6 years until i recently experienced 3 palpatation episodes that stopped me in my tracks. My doctor made it clear that ablation was not an option from the very beginning. We will try to control it with medication and life changes. God willing this will be successful. If the medication neglects to work in the future then a pacemaker is going to be the end result. Hey its not like this is a death sentence and remember, what doesn’t kill ya makes ya stronger! It just makes the handful of us who have been diagnosed with IST thats much more special than everyone else!

  40. Jenny says:

    Hi! Just read your post. I can say I completely understand. I’ve been fighting with IST since I was about 20. I’m now 35. I’ve have 9 surgeries this past 13 months in an attempt to get rid of it and save my life. I had 4 stellate ganglion nerve blocks. I was the first test case at my hospital (THI-Texas Heart Institute) it’s a surgery to “reset” the sympathetic nervous system. We reset my heart and I worked out 2 hours a day to “train” it when to speed up and when to slow down. Sadly the surgeries didn’t hold.

    So I had an ablation. I would up having an AVNRT, so they cured my SVT permanently. But they couldn’t get to my sinus node without damaging my phrenic nerve. SO I had open heart surgery (It’s a new type of open heart they went under my breast and collapsed my lung on that side to make room.) They didn’t break my ribs, they went in between them. Then they used a shield to protect the phrenic nerve and burned the inside and outside of my heart. They burned throughout my sinus node. I did great for 4 months.

    But then I needed a pacemaker. I’m proof that life with a pacemaker is awesome. Please contact me if I can answer any questions for you. I totally understand the desperation this disease causes. I have had a lot of surgeries but I’m going to have a normal life now. I can breathe perfectly. I can move. I can use my arms, and I can’t feel every beat of my heart every waking minute. I can just live and breathe and move. It’s really a miracle.

    I would be glad to talk to you on the phone. I’ll send you pictures of what it looks like to have a pacemaker when you are young. I’d do it a thousand times over again to be able to chase my children and be a normal functional person.

    Best of luck to you!!

    Jenny Ward

  41. Jill comboy says:

    I came across this site after endless hours of searching for information or help on I s t having read other people’s posts its made me feel that I’m not alone. I have a wonder family and friends who without there love and support I would not of coped. I have had a lot a of trouble coping with beta blockers I had 5 so far including antenalol lisinopril, carvedilol none have been sucessful I can cope with the feeling of a racing heart the palpitations and shortness of breath after only walking up a flight of stairs or simply blow drying my hair but its the severe fatigue I suffer from that is a struggle for me. Trying to explain to people that I’m not just tired I’m absolutely exhausted I feel that only people with condition will know how debilitating the fatigue really is. I’m 42 yrs old was a picture of health until the 4 th of June 2012 I went to bed feeling well I woke around 4.30 with severe abdominal pain and vomiting I put it down to a virus but feel I never recovered after numerous doctors appointments and tests a hospital admission weeks turned into months and I’m still ill. I have been made to feel on numerous occasions do people think its all in my head. It’s so helpful to see that other people know what you are going threw, I waiting to see another cardiologist to see what else they can do for I think I would rather have some form of surgery if possible as living on medication for me is so difficult purely down to the fatigue.

  42. Marilyn Hickman says:

    My beautiful daughter Jillian has gone through one year of pure hell going from one diagnosis to another all without confirmation and been passed around Doctor’s some of which have been rude, negative and totally useless in their lack of help and support. She has written her own comments on your website but I would like to add mine. Jillian you are the bravest, strongest person I know and you make me so proud to be your mother! You not only have to suffer these terrible symptoms but also people’s complete lack of understand, ignorance, lack of any sort of sympathy and negative comments by a few people you work with. You have my complete admiration and pride how you have coped with this along with everything else.

    Everyone of you who have what she has to cope with take pride in yourself and there are plenty of us who are proud of you to!

    Love you to the moon and back Jillian

    Mum
    xxxxxxx

  43. Don says:

    Well. I just wanted to drop a short note.. I have not been diagnoised with IST yet, but it sure is pointing me into the right direction..
    I am 40 and have been experience PA, anexity and heart paps since i was 32..

    It all started one night i was at a bar with friends.. Drinking and laughing all was great!
    BAM I felt my HEART BEAT run.. Maybe 120-130.. who knows, but high enough where i said to myself WTF???? WTF is this?? It freaked me out so i said no more drinks of me(i had maybe 2)

    From that time forward i would get “touches” of SINUS TACHY from month to month…especially when i was done working out in the gym or doing cardio.. I really did not know how high my HR was during exercixes, but it NEVER return to my RESTING of 70 -75…

    One say i was jogging and i felt this flutter in my throat.. I check my rate and it must of been 160-170. normally no big deal , but i had only been jogging for like 30secs..

    I was a college athalete from 18-25 and workout hard from 25-30, then settled down with my wife 32.. thats when this stuff happen… I have been to the ER maybe 5 times in the past 8 years.. All for the same thing HIGH HEART RATE with HIGH BP..

    I have a stres test tomorow, maybe the DOC CAN SEE WHAT I SEE WHEN I DO CARDIO WHICH IS BASICALLY
    First 3 mins heart rate gets to 130beats– easy!like walking fast)
    next 3 mins HR get 140-150 but slows down.
    next 3 mins i gotta push it hard to get to 160-170

    JUST AND I MEAN JUST 2 weeks ago i would have to PUSH myself har dot get to 130pulse on exercise.. So for the past 2 years i think i have been dormint cause ihave had good pulse and recovery..

    feel free to email me dax0007AThotmail..good luck to all!

  44. Jessica says:

    I too suffer from IST… I will go from having multiple episodes of palpitations in one day to weeks of being assymptomatic. I was told it was stress by multiple doctors and told I was crazy by family members. I am very healthy with a very fast but normal ekg and a structurally petfect looking heart via echo. The episodes usually happen in the evening and night. I find it is worse after being sedentary for too long. I have elimated caffeine and increased my salt and water intake per my cardiologist. I hope one day I will out grow this condition.

  45. Annette says:

    I barley got diagnosed with this last week it’s been hell I’m taking 275mg of metroprolol a day I just wish this would go away if anyone can email me with advice or just to be a friend ( since my friends and family don’t understand this illness) please email me at nena92385@yahoo.com

  46. Rebecca says:

    Though it was written some time ago, I cannot thank you enough for writing this article. It sums up nicely, what we face each day. I was Dx with SVT/IST last year, and am still having to do my own research to understand the ins and outs, since some doctors don’t care enough to explain what they’ve just diagnosed their patient with. My recurring, worsening issue that brought me back to search out more information, is tachycardia in the 160-170 range while sleeping. Your article has helped me tremendously, thank you so very much! Wish you and your family the best!

  47. Nikaia says:

    For the past 4 years I have been battling a variety of diagnosis regarding my heart issues. First I was diagnosed with Paroxysmal Atrial Tachycardia. Then it got changed to Paroxysmal Supraventricular Tachycardia. More recently it got changed to just Supraventricular Tachycardia. You name the drug, I’ve probably been on it. More recently I developed more problems with Tachycardia and Arrhythmia issues. Yet, another 30 day even recorder showed these things were happening at all times of day and night. So, I was referred to an Cardiac Electrophysiologist for an EP Study with plans for an ablation. What a flop. I came out of it being told that the ablation did not happen and “Sorry, there was nothing I could do.” I now have two different diagnosis. POTS and IST. So now what? I am on Midodrine 10mg , every 6 hours AND 12 1/2 mg of Metroprolol . and that’s it. Today my husband and I had a follow up appt. Once again we were told , sorry.. there is nothing more that can be done. Up until recently I have been a very active preschool teacher. I have danced, hiked, ran with the children I loved to teach. I have had to give it all up because I can no longer function like I want to. I am at a loss on what to do, or where to go. I do not know who to trust. Just when I think the tears are all gone, they come flooding back. I am not one to give up and I wont.. I am just not sure what to do. Sorry if this is a downer.. but this is me for the moment.

  48. Tania says:

    I was so happy to come across this page. I was recently diagnosed with IST and am currently on a roller coaster ride trying to find a medication that helps with side effects I can tolerate. Its a struggle that makes everyday tasks and working challenging at times. I’m a nurse and am very curious why this condition is more common in female health care workers. Have you found any research to possibly explain this? I’ve read many medical journals which help me understand what is known about the condition but I have trouble explaining it to family and friends; this page helped me do that. Thank you for writing it! Hope you have found something that works for you.

  49. Ashlee says:

    Hi my name is Ashlee. First off I would like to thank you sharing your story. Secondly I need an answer or opinion. I am a 17 year old who has been diagnosed with IST, high cholesterol, and bicuspid aortic valve defect. I take lipitor and metaprolol, but I was wondering if either the IST or the heart defect can make each other worse?

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