"Inappropriate Sinus Tachycardia"

Your concern about tachycardia is understandable, @warpedtrekker. As your explain it, a few questions arise that you may wish to discuss in detail with your cardiologist or another cardiologist willing to give you second opinions. First, the diagnosis of "inappropriate sinus tachycardia" is specific to a set of conditions recognizable by a good cardiologist. Has your doctor wondered whether your tachycardia is related to surges of adrenalin -- or some other seemingly separate condition -- that might cause your heart rate to leap up? What role does Bystolic (a drug related to adrenalin) play in your situation? Second, Multaq is advertised as a treatment for patients who once had A-fib. Is that true in your case, but you no longer show signs of it? This question is suggested by your recent EKG and Echocardiogram results, which both show "normal" results.

Your resting heart rate of 70-80 is much like mine; mine also used to be 50-60 until my A-fib diagnosis four years ago. I don't have tachycardia symptoms like yours, but if I did, I would have detailed discussions with two qualified physicians -- separately.

I have seen my primary cardiologist, and then went to two different ones to get second and third opinions. They all had no answer really, why my heart does that. My Electrophysiologist said that "for whatever reason", my brain is telling my sinus node to speed up my heart rate. One doctor did mention possible Adrenaline causing it. But I've had all kinds of blood work done, and my Adrenaline and Thyroid are currently normal. I was also tested for pheochromocytoma and that was negative.

Yes, the EKG/Echo was normal. I assume because I'm on Multaq that is regulating my heart so it wont go back into AFIB. Although my doctor thinks I should try to stop Multaq and see what happens. If it goes back into AFIB, may need to get an ablation at some point.

I'm taking Bystolic, mainly to help control heart rate, and to counteract potential "Long QTC" that Multaq can cause. My blood pressure is fine, and usually 110/70 or so. Although when I have these tachycardia episodes, it will shoot up to 150/100 easily.

Today I had unusual high resting heart rate. 95-105bpm. Usually around 100bpm, just sitting down at my desk at work. It stayed there all afternoon, until I took my nightly Bystolic and Multaq. Basically my heart rate will just "stick" at a high rate and stay there for hours. I don't know why. It makes me feel uneasy. So sometimes I take a half-tablet "Klonopin" to see if it is anxiety driven, or an extra "Bystolic" per my doctor. It will then sometimes go back down to normal.

Is taking beta blockers the only treatment for IST? Or would I need an ablation?

Well, @warpedtrekker, it looks like you're right on top of your situation and well endowed with professional medical help. I'm particularly impressed that your medical team tested you for pheochromocytoma which could double your epinephrine (adrenalin) and boost your heart rate and your blood pressure. But despite all that you and your medical team have done to investigate and treat your symptoms, there is still the mystery. I wonder, though, whether the face-off between your Multaq and your Bystolic might be problematic, since they can pull in opposite directions. I can't answer your question about beta blockers for IST (I just don't know), but I have read that the "inappropriate" level of electrical stimulus in the atrial sinus node is sometimes attributable to forces from elsewhere in the body or its processes (that's where the adrenalin suspect fits in, for example). Nor will I venture a guess on how an ablation might correct the problem with your sinus node.

My main problem (hypertension) stayed in the wild for 20 years with internists and cardiologists guessing about the cause; then my HMO adopted a rule that enduring hypertension must be treated first by a nephrologist. After two second opinions, I fell under the care of a brilliant woman whose father is the leading cardiologist in her home state (so she had expert resources most other doctors don't enjoy). Determined to figure out my problem, she called in an endocrinologist, and together they examined every hormone they could think of. Result: I tested positive for a congenital kidney defect known as Liddle Syndrome -- my kidney is unable to reclaim and preserve the potassium it casts out along with sodium ions. I'm hypokalemic!! No more! First, prune juice gave me the potassium I needed, and now I'm a moderate consumer of coconut water. Main benefit is I can double up on antihypertensive meds without fear of dying from excess potassium (hyperkalemia). Now, if I could get my a-fib under control, I could govern the world!!

I hope that you and your imposing medical team can stay on top of your conditions and find the key to your tachycardia. Given the experience you have had with it, I'm confident that you have the insights and the stamina to see it through to victory. Martin

@warpedtrekker I’ve had tachycardia for more than 20 years. My heart rate when I’m sleeping is 145.
When I was first tested doctors asked me numerous times if my heart raced just upon standing. They said if it did that was something different called POTS and it would require different treatment than my sinus node tachycardia. I don’t have POTS but it might be worthwhile for you to check that out.
I was told that there really is no good researched treatment for tachycardia. Couple of years ago I was put on Ivabradine which worked and controlled my heart rate. Unfortunately insurance wouldn’t cover it because it was prescribed for me “off label”. So, I was switched to Flecainide which is a med for people with afib. It works for my tachycardia but I had to be closely monitored for the first year with monthly ekg. Now I only get checked yearly.
Hopefully this gives you some thoughts for questions to ask your cardiologist. Best of luck to you. Here’s to a happy and healthier new year!

I have sinus tachycardia all my life
It did go into 80s more so high 80s occasionally but since my late thirties stuck well above 100 at all times. I’m pretty symptomatic, but I’m now on Ivabradine and manage better on it otherwise I was totally non functional
I wonder why some people are symptomatic and some are not with this problem. My pulse is much slower during sleep although I do get tachycardia asleep too, just it also has slower rates than awake.
My unmedicated resting is around 100-130s

Forgot to add: my cardiologists are unhelpful in terms of saying it’s anxiery causing symptoms. They said ‘your body should get used to =adapted to sinus rhythm’. I never had that happen and it got steadily worse since I was around 14. I’ve has this problem much earlier, at least 7 year old, when it was first noticed to be racing. Does your cardio explain why disabling symptoms happen or do they claim you are having anxiety and mental illness somatic syndrome and the like?
I’m very tired of being dismissed and wonder which authority can I show to them to prove it’s a real illness which causes disability not my mind.

Hi there, my name is Karen, I'm 32 yo and I've been a member here on Connect for awhile now, but I usually stay within the neurology boards due to my conditions. However, for the last year or so I've developed chronic (inappropriate, I guess is the correct term?) sinus tachycardia w/ regular PVCs etc. My resting heart rate stays around 120+ and my BP is either normal or somewhat low. I get short of breath and lightheaded a lot while doing nothing, I'm fatigued all the time, constantly feeling like I just ran a half marathon, when in reality all I was doing was standing or sitting. I do have orthostatic hypotension, but this seems to be very different and "out of nowhere." I see a chiropractor regularly so I know that my vagus nerve is not a problem here. My Dr prescribed metoprolol 25mg in the past, but it didn't really seem to help. I got represcribed it today, so I plan to give it another shot. But, I'm really wondering about what could possibly be causing this? Anxiety and stress have both been ruled out. I'm frustrated bc I used to be really active and I'm having a hard time functioning at work / home w/o wanting to sleep or rest all the time. I want to be active again and for my quality of life to increase. I know a lot of it's all in your perspective, but even still... Any thoughts? Thanks ya'll.

Hi Karen @rivermaya34, Sorry to hear you have another difficult condition to deal with. It can't be easy when you are constantly dealing with fatigue. You mentioned being on metoprolol in the past and it didn't help much but you are going to give it another try. I ran across an article from 2018 that you may want to discuss with your doctor or cardiologist.

"Managing patients with IST includes lifestyle modification, non-pharmacological and pharmacologi-cal interventions. Ivabradine has recently emerged as an effective treatment of IST and was shown to be superior to beta-blockers."
--- Challenges in Treatment of Inappropriate Sinus Tachycardia: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872261/

Did the doctor or cardiologist prescribe the metoprolol for the inappropriate sinus tachycardia?

@johnbishop Hey John, thanks for sharing this article. I was actually just reading about the same drug when you sent this. When I go back in 6 weeks, I definitely will be asking about it and what the plan is moving forward. It's awful, I wouldn't wish this on anyone. I just hope it eventually resolves or slows down (not to a dangerous rate, obviously) so I can "breathe" again. In the meantime, I'm gonna be talking with the clinical pharmacist at work, who's a good friend of mine and top of her class, really knowledgeable. She's always able to dig up obscure research / journal articles / studies with a lot of valuable information. I go back to a couple of my Dr's in 6 weeks to discuss this more. And, in answer to your last question, yes he did prescribe it for that reason.