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At what heart rate is svt dangerous?
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At what heart rate is svt dangerous?

  I have been diagnosed in the past with svt and told it was not life threatning, but the more I read I wonder if that is the case. I read where if your heart gets up to 120 to 160 that it is dangerous. My heart is just getting started at 160. To me, that is nothing. When I wore the holter monitor and event recorder just a coulple to three weeks ago for skipping beats, it picked up some svt of 160 and some higher and the cardiologist wasn't concerned. I would like to know when to be scared and alarmed. I also would like to know what is the difference in being diagnosed with just plain old svt and AVNRT? My diagnoses on my last event recorder showed psvt.. Then it showed up that my heart had three and four beats in a row at bmp231 and one pause for 2.1 second. I looked that up on the internet and it suggests that, that could be VT, and I know that is dangerous. But once again my cardiologist said you could have four to seven beats in a row and it not be dangerous. He said you would have to have about thirty in a row for thirty seconds to be really dangerous. I am just confused as to what is dangerous and when there is a need to be alarmed and when there is not. Seems what you read on the internet is quite different than what your cardiologist tells you. Could someone please help me understand this and ease my worries?
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1124887_tn?1313758491
SVT = supraventricular tachycardia

Supraventricular tacycardia is a joint term for all tachyarrhythmias that origin above the ventricules;

Sinus tachycardia (so common that it's usually not mentioned within SVT)
AV nodal reentry tachycardia (AVNRT)
Ectopic atrial tachycardia (EAT/AET) - uni and multifocal
Junctional ectopic tachycardia (JET)
Quick AF / Aflu (>100 bpm) is considered tachycardia.

It's important to differ the SVT in supventricular tachycardia from the SVT in sustained ventricular tachycardia (the term SVT is rarely used for VT due to risk of confusions, though, but what you explain above is sustained VT and not supraventricular tachy.)

Your symptoms is as taken out of the book for ectopic atrial tachycardia or AVNRT. I can explain the difference.

AVNRT is a phenomenon were an electrical impulse get "stuck" in your AV node (between atrias and ventricles) going around and around, and does not stop until it's either "wiped out" by another PAC (a PAC initially triggered it) or you induce a short AV block, with parasympathic stimulants/valsalva or adenosine at the ER. AVNRT is caused by an extra pathway in your AV node and is curable with ablation.

Ectopic atrial tachycardia is just a line of PACs (triplet or longer) from an "extra pacemaker" in your upper chambers. If it was just 4 beats, and at HR 231, it's likely this, and not AVNRT (though only a doctor would know for sure). The pause afterwards is very common, just as a pause after a PAC or PVC.

Short runs of high HR will not hurt you. I read about an experiment on a pig (with heart fairly similar to humans) where they put it on pacemaker with HR 240 for three weeks, inducing dilated cardiomyopathy and heart failure, but that was 3 weeks non-stop! (I was curious about this too). That was a line of 7,2 million heart beats at rate 240.

The danger is going with quick Afib (rate 150 or more) for months and years, and certain, fast versions of IST (with similar quick HR).

Short events of atrial tach is a normal phenomenon. As long as you have measured it and is sure it's atrial, and it doesn't last for several hours, it's normal.


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1308156_tn?1273438605
Thanks for explaining all of this, but forgive me if I am still a little confused. You seem to be very well educated on all of this. I thought if you had a line of pac's or pvc's that it was called vt. And when I had the three beats of 231bpm was it sustained vt or ectopic atrial tachycardia? When I read what you wrote seems like you are saying it could be both. Maybe it is the way I am reading it. I get confused easily.Also, how can they tell that my heart rate is 231bpm just from three beats and 160bpm from only four beats? Looks like it would have to have stayed that way for a minute for them to tell this. The heart dr. didn't seemed concerned at all. I asked him if this meant I was having vt and he said no. Does this make me more likely to have vt at some point? Whenever my heart rate goes up and I have svt and the event recorder picks it up, it never shows any pvc's or pac's. It just shows that I went into svt all of a sudden on its own with no extra beats. And can your heart really skip a beat and if so what is it called?
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1124887_tn?1313758491
Hello,

Line of PVCs = VT
Line of PACs = SVT (or ectopic atrial tachycardia, that is a specific form of SVT)

Generally:

VT = possibly dangerous, dependent of the cause
SVT = almost always benign, if it's not sustained for long time, occurring very often, etc.

If you have a line of 4 beats, without being monitored, it's hard to say what it is. It's usually SVT and not VT, though, as the first one is common and the other one is uncommon.

If your doctor is not worried, neither should you be. Short runs of SVT are common in normal hearts from time to time.

(I don't know very much about this, by the way)..

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1308156_tn?1273438605
  Thanks for explaining the difference between the two. Sorry to have asked so many questions. You do seem to know alot about all of this compared to me. Thanks for caring! :)
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1308156_tn?1273438605
  How do you post a question for the dr. forums in the expert forums? I clicked on ask a dr. a question and it takes me to where other people have asked questions, but I didn't see anywhere where it allowed me to post a question for them.
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6675833_tn?1383654523
Having had a heart monitor for 24 hours the cardio specialist is going to insert an ILR  as he says the monitor showed an SVT and he thinks 2 falls within the last 2 months are linked. He thinks that I either collapsed or blacked out and it is possible it was caused by SVT`s even though I am adamant that I did neither collapse or blackout as I remember everything. Would an SVT do this as there was only one in the 24 hour period?
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1423357_tn?1414258965
Why does the cardiologist want to use an ILR?  If your SVT events are that far apart that an ILR is necessary, I wouldn't worry about them.  If your events were like mine, 3 to 5 times per month, a 30 day wearable recorder will be sure to catch at least one as my recorder did. I've seen a number of people on here with ILR's for more serious cardiac conditions complain about pain, and infection following and ILR procedure.

Holters are often useless with SVT due to its paroxsysmal nature. If you were fortunate to record one, that good news for you.  I had SVT for 54 years, and have been on this forum for 3 years.  I never experienced or have read here of anyone blacking out from an SVT event.  There is a possibility if your HR was really, really fast that your ventricles wouldn't fill fast enough and you'd start to feel light-headed and perhaps be a bit cyanotic, bluish lips and nail beds.  I use to get them all the time, even competing in cycling and skating events, and a lot of the time, I'd finish the event while in SVT.

I'm amazed at the number of GP's and even cardiologists that don't seem to have a good handle on SVT.  I once told one that should experience it for himself when he suggested that it was only anxiety.  Stick to your guns, and I'd really think more about the ILR.  Perhaps a second opinion would be helpful too.
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Avatar_m_tn
I have gone to the ER more times than I an count for SVT/PSVT with a heart rate o 148 to over 200 beats per minute.  Every time I go it costs over $2,000.00 for chemical cardioversion. Using Adenosine (Adenocard).  Prior to going I try these Valsalvo maneuver, Eyeball pressure, Coughing, carotid massage,  What usually works the best is quite traumatizing.  I get 2 large pitchers of ice water.  I lie down in the tub and my husband quickly dumps the water on my upper body and face. I have had SVT continuously for over 8 hours.  It eventually causes an enlarged heart.  I am 59 years old. have had this since my mid 30's.
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1398166_tn?1358874123
Go to an EP and look at an ablation.
Are you an RN and not aware of this?
It will cost your max out of pocket, but could work for you, possibly.
Get started on it, because it will take a month or more to get into the specialist.
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1423357_tn?1414258965
A face plant into a shallow pan of ice water is a proven method for converting SVT.  Others have stated here that a brief headstand worked for them.  Valsalva always worked for me in the 54 years that I had SVT.  I got mine fixed at 59.
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