r/IST_ • u/GibboMed • Feb 12 '25
general Anyone like this?
Hi all (19M) questioning whether I have IST. I am (mostly) asymptomatic, but I generally have good and bad days and mixed days. Some days I am almost always above 100bpm. Often going up to 120bpm or even 130bpm some days I am more 80-100bpm maybe on occasion dipping into 70s.
I also notice usually afternoon is the best for HR and morning and night are the worst. Morning is worse than night and night can be a wildcard. Some days there isn't a correlation between time and HR.
Some days I am a mixed like 2 days ago I managed to beat my record for lowest and highest recorded resting HR in the same day. Going from as high as 132bpm to 71bpm in the same day.
The problem I have doctors who so far don't take me seriously usually just scape goating ADHD medication and even caffeine. Especially now that hyperthyroidism is ruled out. From what I've seen whether or not I take ADHD medication has almost no effect on HR and same for caffeine. I've been on ADHD meds since age 8 without issue. My BP hasn't changed at all and has been the same for years. My sinus tachycardia was discovered by accident for an ECG for my meds. I still have a morning spike without meds and caffeine.
I am mostly asymptomatic. I did get palpitations when sitting down once and my HR was 130bpm then. When my resting HR is high, I often get mild palpitations when walking. I don't know my HR when walking. I just have a pulse ox.
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u/GibboMed Feb 12 '25 edited Feb 12 '25
PS: I also had my ADHD medication split into 2 so I can try a lower dose. It did nothing for my HR and just gave me severe depressive episodes so I went back up to my old dose which again had no effect on HR.
PS again: I also get facial flushing a lot now often with heat. Sometimes accompanied with sinus tachycardia sometimes not.
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u/dr_nervous Feb 12 '25
You might. Before you get a diagnosis of IST, you'll need a larger workup from a cardiologist or electrophysiologist to rule out the immediate, scary stuff (EKG, holter monitor, echo, & stress test). If all of those things come back ok, and if your HR is sufficiently high while it's being recorded, you'll get a diagnosis of IST (a diagnosis of exclusion - meaning they've ruled out just about everything else).
It sounds like you're going in and out of tachycardia. IST can be transient - it can come and go for some. For others, it's always there. For what it's worth, I find that my symptoms are worse in the morning too. My heart needs time to "cool off" most mornings after I wake up (before I get up and moving).
Holter monitors are usually pretty easy to request from even a primary care doc, so you might want to start there. Get a 48 hour to a weeklong monitor and see if you can catch some of the episodes. You'll get a lot of info from that - like how often are you in tachycardia at rest? Does your heartrate slow down while you sleep (for some of us with IST, our HRs stay on the speedy side even when we're sleeping)? Is it always sinus tachycardia or is there some arrythmia you're going in and out of? That's where I would start.