u/AthleteNo198

Hi everyone,
I’m a 22-year-old male and 2026 has honestly turned my life upside down. I’m hoping someone here has been through something similar or can point me in the right direction because I’m feeling pretty lost.
Everything started in January after I caught what seemed like a normal winter virus. I had a mild fever one night, but what concerned me was that my resting heart rate stayed around 130 bpm while I was lying in bed. I got up to talk to my parents and noticed my heart rate climbing even higher. I checked it on my pulse oximeter and it was in the 160s while I was just sitting on the couch. As I started panicking, it continued climbing, so my family called 911.
When the paramedics arrived, they hooked me up to their monitor and my heart rate was around 215 bpm. I was extremely short of breath and terrified. After looking at the ECG, they told me I was in SVT. They gave me two doses of adenosine at my house. I converted after the second dose but went back into SVT a couple of minutes later. In the ambulance they gave me another dose, had me do a modified Valsalva maneuver, and used ice packs on my chest, neck, and face. That finally converted me back to sinus tachycardia. Once I got to the hospital, they gave me diltiazem over several hours until my heart rate returned to normal. The ER doctor diagnosed SVT and referred me to a cardiologist.
Over the next month I had two more episodes. One happened at my primary care doctor’s office where my heart rate stayed around 160 bpm for nearly two hours. The other happened on the way to my cardiologist for an echocardiogram. My workup included blood work, an echocardiogram, and a 6-day Holter monitor. Ironically, I had another episode two days after the monitor was removed, so it didn’t capture it.
After that, my cardiologist started me on metoprolol tartrate, and thankfully I didn’t have another episode while taking it. My resting heart rate was usually in the 50s-60s.
The downside was that after about 3-4 months I started having pretty significant side effects. I have a history of asthma, and I developed chest pressure, shortness of breath with exercise, and really poor exercise tolerance. My cardiologist decided to switch me from metoprolol to diltiazem and told me I didn’t need to taper the metoprolol—I could just stop it and start diltiazem.
Unfortunately, two days later, after spending an entire day shaking, sweating, and having rebound high blood pressure, I had another SVT episode. This time I could briefly convert with the Valsalva maneuver, but it kept coming right back. I ended up back in the ER, where I received metoprolol again, and after another Valsalva maneuver my heart rate finally returned to normal.
After that episode, everyone recommended I see an electrophysiologist (EP). I was honestly excited because I thought I was finally getting closer to a long-term solution like an ablation.
The EP I originally wanted to see wasn’t available, so I saw another physician instead. He explained catheter ablation and said it’s generally a straightforward procedure, but as the appointment went on I felt like he became increasingly dismissive.
One thing that really confused me was that he told me, “If you had true SVT, the first dose of adenosine would have converted it immediately.” That didn’t really make sense to me because adenosine has such a short half-life, and I know factors like IV placement and administration can affect how well it works.
Another factor is that I have a tic disorder and take clonidine (off-label) every six hours for my tics. The EP felt that my symptoms sounded more like Inappropriate Sinus Tachycardia (IST) because my heart rate increases when I stand up or eat. I explained that eating often triggers my tics and anxiety, which raises my heart rate into the 120-130 range.
He also suggested I might be experiencing clonidine withdrawal causing rebound tachycardia. That doesn’t seem to fit my situation because clonidine has roughly a 12-16 hour half-life, and I take it every six hours consistently. I’ve even had episodes less than an hour after taking a dose.
At the end of the visit, he recommended stopping both metoprolol and clonidine because of their side effects. He also said he doesn’t want to perform an EP study or ablation unless he has a clean 12-lead ECG showing the arrhythmia.
Here’s where I’m stuck.
I have multiple single-lead recordings showing heart rates around 200 bpm with an abnormal rhythm. The hospital and paramedics diagnosed SVT multiple times. However, when I requested my records, the hospitals apparently didn’t save the 12-lead ECGs from those episodes—only the rhythm strips/single leads.
His recommendation was basically to stop my medications and, if I have another episode, go to the hospital and get a clear 12-lead ECG.
The problem is that during these episodes my tic disorder becomes extremely severe. I’m having forceful chest and upper-body tics, so staying perfectly still long enough to obtain a clean 12-lead ECG is incredibly difficult.
At this point I feel like I’m back at square one after spending months being treated for SVT.
I’ve already contacted my care navigator and requested a referral to the original EP I wanted to see for a second opinion.
Today is also my first day tapering off metoprolol using my cardiologist’s updated taper schedule:
Once daily for one week
Every other day for one week
Then discontinue
I’m obviously nervous about how that’s going to go.
This whole experience has completely changed my life. Before all of this I had a great job in robotics, traveled regularly, and played golf every week. Over the past six months I’ve basically had to put my life on hold.
So I have a few questions:
Has anyone here been diagnosed with SVT only to later be told it was IST?
Would you seek another EP opinion before accepting that conclusion?
Has anyone had difficulty getting documentation of an arrhythmia because episodes were intermittent or because movement artifact made ECGs difficult?
Any recommendations for experienced EPs in Southern California?
I know nobody here can diagnose me, but I’d really appreciate hearing from anyone who’s had similar experiences. Being 22 and trying to navigate all of this has been incredibly frustrating.
Thanks for reading.

22M - Diagnosed with SVT, now an EP thinks it’s IST. Feeling completely stuck and looking for advice (SoCal)
Hi everyone,
I’m a 22-year-old male and 2026 has honestly turned my life upside down. I’m hoping someone here has been through something similar or can point me in the right direction because I’m feeling pretty lost.
Everything started in January after I caught what seemed like a normal winter virus. I had a mild fever one night, but what concerned me was that my resting heart rate stayed around 130 bpm while I was lying in bed. I got up to talk to my parents and noticed my heart rate climbing even higher. I checked it on my pulse oximeter and it was in the 160s while I was just sitting on the couch. As I started panicking, it continued climbing, so my family called 911.
When the paramedics arrived, they hooked me up to their monitor and my heart rate was around 215 bpm. I was extremely short of breath and terrified. After looking at the ECG, they told me I was in SVT. They gave me two doses of adenosine at my house. I converted after the second dose but went back into SVT a couple of minutes later. In the ambulance they gave me another dose, had me do a modified Valsalva maneuver, and used ice packs on my chest, neck, and face. That finally converted me back to sinus tachycardia. Once I got to the hospital, they gave me diltiazem over several hours until my heart rate returned to normal. The ER doctor diagnosed SVT and referred me to a cardiologist.
Over the next month I had two more episodes. One happened at my primary care doctor’s office where my heart rate stayed around 160 bpm for nearly two hours. The other happened on the way to my cardiologist for an echocardiogram. My workup included blood work, an echocardiogram, and a 6-day Holter monitor. Ironically, I had another episode two days after the monitor was removed, so it didn’t capture it.
After that, my cardiologist started me on metoprolol tartrate, and thankfully I didn’t have another episode while taking it. My resting heart rate was usually in the 50s-60s.
The downside was that after about 3-4 months I started having pretty significant side effects. I have a history of asthma, and I developed chest pressure, shortness of breath with exercise, and really poor exercise tolerance. My cardiologist decided to switch me from metoprolol to diltiazem and told me I didn’t need to taper the metoprolol—I could just stop it and start diltiazem.
Unfortunately, two days later, after spending an entire day shaking, sweating, and having rebound high blood pressure, I had another SVT episode. This time I could briefly convert with the Valsalva maneuver, but it kept coming right back. I ended up back in the ER, where I received metoprolol again, and after another Valsalva maneuver my heart rate finally returned to normal.
After that episode, everyone recommended I see an electrophysiologist (EP). I was honestly excited because I thought I was finally getting closer to a long-term solution like an ablation.
The EP I originally wanted to see wasn’t available, so I saw another physician instead. He explained catheter ablation and said it’s generally a straightforward procedure, but as the appointment went on I felt like he became increasingly dismissive.
One thing that really confused me was that he told me, “If you had true SVT, the first dose of adenosine would have converted it immediately.” That didn’t really make sense to me because adenosine has such a short half-life, and I know factors like IV placement and administration can affect how well it works.
Another factor is that I have a tic disorder and take clonidine (off-label) every six hours for my tics. The EP felt that my symptoms sounded more like Inappropriate Sinus Tachycardia (IST) because my heart rate increases when I stand up or eat. I explained that eating often triggers my tics and anxiety, which raises my heart rate into the 120-130 range.
He also suggested I might be experiencing clonidine withdrawal causing rebound tachycardia. That doesn’t seem to fit my situation because clonidine has roughly a 12-16 hour half-life, and I take it every six hours consistently. I’ve even had episodes less than an hour after taking a dose.
At the end of the visit, he recommended stopping both metoprolol and clonidine because of their side effects. He also said he doesn’t want to perform an EP study or ablation unless he has a clean 12-lead ECG showing the arrhythmia.
Here’s where I’m stuck.
I have multiple single-lead recordings showing heart rates around 200 bpm with an abnormal rhythm. The hospital and paramedics diagnosed SVT multiple times. However, when I requested my records, the hospitals apparently didn’t save the 12-lead ECGs from those episodes—only the rhythm strips/single leads.
His recommendation was basically to stop my medications and, if I have another episode, go to the hospital and get a clear 12-lead ECG.
The problem is that during these episodes my tic disorder becomes extremely severe. I’m having forceful chest and upper-body tics, so staying perfectly still long enough to obtain a clean 12-lead ECG is incredibly difficult.
At this point I feel like I’m back at square one after spending months being treated for SVT.
I’ve already contacted my care navigator and requested a referral to the original EP I wanted to see for a second opinion.
Today is also my first day tapering off metoprolol using my cardiologist’s updated taper schedule:
Once daily for one week
Every other day for one week
Then discontinue
I’m obviously nervous about how that’s going to go.
This whole experience has completely changed my life. Before all of this I had a great job in robotics, traveled regularly, and played golf every week. Over the past six months I’ve basically had to put my life on hold.
So I have a few questions:
Has anyone here been diagnosed with SVT only to later be told it was IST?
Would you seek another EP opinion before accepting that conclusion?
Has anyone had difficulty getting documentation of an arrhythmia because episodes were intermittent or because movement artifact made ECGs difficult?
Any recommendations for experienced EPs in Southern California?
I know nobody here can diagnose me, but I’d really appreciate hearing from anyone who’s had similar experiences. Being 22 and trying to navigate all of this has been incredibly frustrating.
Thanks for reading.