Aa
What is relation between IST and SVT?
I have suffered Inappropriate Sinus Tachycardia from age 17 to present (age 35), which has been well controlled by 25mg atenolol daily. If I am not on atenolol, my resting heart rate is borderline tachycardic, and shoots up to 100-120+ at the drop of a hat, upon exertion, standing suddenly, hot temperature, etc.
Is it peculiar that someone would have both IST and tre re-entrant SVT (AVNRT)? Do most people with re-entrant SVT have normal heart rates outside of their episodic SVT?
Is it peculiar that someone would have both IST and tre re-entrant SVT (AVNRT)? Do most people with re-entrant SVT have normal heart rates outside of their episodic SVT?
From what I understand IST a lot of times is caused by issues outside the heart like autonomic disorders or thyroid disorders or even medication. In Sick Sinus Syndrome the SA node is having issues producing a steady beat and then other parts of the heart can take over the beating. AVNRT is a reentrant svt that is marked by rates 200 and above but there are other SVTs that don't present at such fast rates. WPW is one that may cause a circuit that goes all the way around the heart as opposed to just around the AVnode which is what makes AVNRT go so fast. I was told by my EP that one can present at rates even as low as 150s or 160s. Generally though there is a tell tale sign on the EKG even when one is not in tachycardia that indicates one has wpw. AVRT is also one that may or may not present at super high rates. This said, when you discuss this with your EP I would highly suggest getting clarification on what they saw and explain to them that you do not feel the abrupt start or stop. Be very vocal and clear what you are feeling and getting your questions answered. Have them written down so you don't forget to ask one while you have the EPs attention.
As a person who had AVNRT her whole life and only had it ablated recently my heart rate has always run pretty high. Now that I am exercising it is starting to slow a bit as well possibly getting the svt corrected slowed it down. My heart rate would be elevated for a few days after an episode more so than normal where it would elevate to the 130s or more upon light exertion. As well eating a very heavy meal can still bring on this sort of rate for me. So I suspect repeat episodes of anxiety attacks or any sort of svt can leave the heart beating a little faster than normal for a few days. The heart is very resilient but it does take a while for it to settle down considering it has to keep pumping regardless of the strain that has been put on it.
As a person who had AVNRT her whole life and only had it ablated recently my heart rate has always run pretty high. Now that I am exercising it is starting to slow a bit as well possibly getting the svt corrected slowed it down. My heart rate would be elevated for a few days after an episode more so than normal where it would elevate to the 130s or more upon light exertion. As well eating a very heavy meal can still bring on this sort of rate for me. So I suspect repeat episodes of anxiety attacks or any sort of svt can leave the heart beating a little faster than normal for a few days. The heart is very resilient but it does take a while for it to settle down considering it has to keep pumping regardless of the strain that has been put on it.
ok we are crossing wires here. I posted the above before I saw your recent one....sorry about that!!
I just read you other post. One other comment.
I generally find my anxiety levels dropping when I work to understand my condition. However, when I first starting learning, I must admit that I got incredibly anxious and depressed. I then found out that this is a common response suffered by people who have to go to a cardiologist for one reason or another. We start obsessing too much about this, lose sleep, and then get anxious and depressed.
Do not allow yourself to get depressed. Most of these heart rhythm issues, especially simple re-entrant SVT's are harmless. Even a more ugly diagnosis like "VT" may not amount to a major concern. You can do alot more good for yourself by keeping your cool, and just learn about what's what. Its a very technical area. Keep in mind that there is a learning curve involved. The understanding you need will come. If spend your time learning instead of being depressed and freaking out, you can do a better job of managing your health care.
As far as heart rate goes, SVT's tend to max out at lower heart rates, and 250bpm is probably an upper limit on AVNRT. If you max out at only 180, you are probably in good shape, especially if it occurs a lot. If this occurs alot, and you have a true SVT, it may end up being easier to find during and ep study, which means the likelihood of you having to deal with this problem for any length of time could be smaller than you realize at this point....
Sorry to have missed your earlier post. (And sorry to hear your heart rhythm troubles).
I generally find my anxiety levels dropping when I work to understand my condition. However, when I first starting learning, I must admit that I got incredibly anxious and depressed. I then found out that this is a common response suffered by people who have to go to a cardiologist for one reason or another. We start obsessing too much about this, lose sleep, and then get anxious and depressed.
Do not allow yourself to get depressed. Most of these heart rhythm issues, especially simple re-entrant SVT's are harmless. Even a more ugly diagnosis like "VT" may not amount to a major concern. You can do alot more good for yourself by keeping your cool, and just learn about what's what. Its a very technical area. Keep in mind that there is a learning curve involved. The understanding you need will come. If spend your time learning instead of being depressed and freaking out, you can do a better job of managing your health care.
As far as heart rate goes, SVT's tend to max out at lower heart rates, and 250bpm is probably an upper limit on AVNRT. If you max out at only 180, you are probably in good shape, especially if it occurs a lot. If this occurs alot, and you have a true SVT, it may end up being easier to find during and ep study, which means the likelihood of you having to deal with this problem for any length of time could be smaller than you realize at this point....
Sorry to have missed your earlier post. (And sorry to hear your heart rhythm troubles).
hi, Bromley, thanks for your reply.
According to Richard Fogoros, M.D.:
"One special variety of automatic SVT is not due to an acute illness, and tends to be chronic and difficult to manage: Inappropriate sinus tachycardia (IST)"
http://heartdisease.about.com/od/palpitationsarrhythmias/a/Types-Of-Supraventricular-Tachycardia-Svt.htm
>"When you say that your heart rhythmn changes at the "drop of a hat", you could be referring to a re entrant tachycardia like AVNRT or SNRT. By "abrupt", I mean absolutely instantaneously. "
I was more referring to tachycardias that come on due to exertion, standing up, exercising, heat, etc. If I rise from a seated position and walk 20 yards, my HR will reliably go up 30-40 BPM sometimes, with absolutely minimal exertion, out of all proportion to my expenditure of energy. This is classic IST, exertion intolerance. It is not like a classic SVT episode, from what I gather, where a person can be sitting on the sofa and have his heartrate go from 60 to 200 in one heartbeat. That's not my experience.
But my cardiologist has informed me that I experienced a re-entrant PSVT which was recorded on a 30-day event monitor.
It seems like the two things (IST and SVT) would be related, if they occurred in the same person.
According to Richard Fogoros, M.D.:
"One special variety of automatic SVT is not due to an acute illness, and tends to be chronic and difficult to manage: Inappropriate sinus tachycardia (IST)"
http://heartdisease.about.com/od/palpitationsarrhythmias/a/Types-Of-Supraventricular-Tachycardia-Svt.htm
>"When you say that your heart rhythmn changes at the "drop of a hat", you could be referring to a re entrant tachycardia like AVNRT or SNRT. By "abrupt", I mean absolutely instantaneously. "
I was more referring to tachycardias that come on due to exertion, standing up, exercising, heat, etc. If I rise from a seated position and walk 20 yards, my HR will reliably go up 30-40 BPM sometimes, with absolutely minimal exertion, out of all proportion to my expenditure of energy. This is classic IST, exertion intolerance. It is not like a classic SVT episode, from what I gather, where a person can be sitting on the sofa and have his heartrate go from 60 to 200 in one heartbeat. That's not my experience.
But my cardiologist has informed me that I experienced a re-entrant PSVT which was recorded on a 30-day event monitor.
It seems like the two things (IST and SVT) would be related, if they occurred in the same person.
IST is not generally considered a form of SVT. However, SNRT is.
In IST, your SA node (i.e. natural pacemaker) runs too fast which leads to a fast, but otherwise normal heart beat. In IST your heart rate normally becomes fast and then normal slowly. In SNRT, a reentrant circuit in or near your SA node causes a fast, but otherwise normal heart beat, but the heart rate normally becomes fast abruptly and then normal abruptly.
When you say that your heart rhythmn changes at the "drop of a hat", you could be referring to a re entrant tachycardia like AVNRT or SNRT. By "abrupt", I mean absolutely instantaneously.
AVNRT heart rates tend to be higher than heart rates for SNRT. It is less likely, but presumably possible, that you would find SANRT and AVNRT in the same heart. It would certainly be easy to recognize and/or distinguish between the two on an ecg however.
Many people with reentrant tachycardia have normal heart beats most of the time, aside from their episodes of SVT. Some with SVT have heart beats and/or heart rates that are just not normal most or all of the time.
In IST, your SA node (i.e. natural pacemaker) runs too fast which leads to a fast, but otherwise normal heart beat. In IST your heart rate normally becomes fast and then normal slowly. In SNRT, a reentrant circuit in or near your SA node causes a fast, but otherwise normal heart beat, but the heart rate normally becomes fast abruptly and then normal abruptly.
When you say that your heart rhythmn changes at the "drop of a hat", you could be referring to a re entrant tachycardia like AVNRT or SNRT. By "abrupt", I mean absolutely instantaneously.
AVNRT heart rates tend to be higher than heart rates for SNRT. It is less likely, but presumably possible, that you would find SANRT and AVNRT in the same heart. It would certainly be easy to recognize and/or distinguish between the two on an ecg however.
Many people with reentrant tachycardia have normal heart beats most of the time, aside from their episodes of SVT. Some with SVT have heart beats and/or heart rates that are just not normal most or all of the time.
clarification: IST is technically an SVT, but I am asking about relationship between IST (a so-called "automatic" SVT, according to sources I have read) and re-entrant SVT (the condition that is generally associated with the term "SVT" whose origin is not the sinus node).
Have an Answer?
You are reading content posted in the Heart Rhythm Community
Are there grounds to recommend coffee consumption? Recent studies perk interest.
Salt in food can hurt your heart.
Get answers to your top questions about this common — but scary — symptom
How to know when chest pain may be a sign of something else
A list of national and international resources and hotlines to help connect you to needed health and medical services.
Herpes sores blister, then burst, scab and heal.
