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NSVT questions

Thanks in advance for answering our questions. Posted a while back, so this is my 2nd question for the 6 months. I've had all the tests and they were all negative, holter, nuclear stress test and echo. Holter showed 6 SVT episodes and a handful of PVC's/PAC's.
1. You mentioned NSVT feels exactly the same as SVT in most people, I've heard SVT described as just fast but regular, can it feel irregular, like a rhythm thats "stuck"?
2. The NSVT episodes I feel I had were within a month or so and haven't occured since in about 7 months.  Could they have been triggered by outside factors at the time of the occurences such as too much caffeine, smoking, being overweight and eating poorly? Or do those factors simply aggravate an underlying condition?
3. If they were caused by any of those factors alone, if I were to change those habits, is it likely they may never happen again or if a person experiences NSVT are they more likely prone to more occurences over their lifetime?
4. Being that they were isolated to that time frame, does that point to outside factors as the possible cause?
5. Whats to keep NSVT from continuing into VT in a healthy, normal heart?  
6. What regulates a rhythm like bigeminy or trigeminy as opposed to just having random frequent PVC's?

I can handle the isolated PVC's/PAC's, its the runs that I feel I had last year that have me concerned. I thought nothing of them at the time but since I've had an increase and change in PVC's/PAC's, it feels like its just a matter of time before those runs return. Any reassurance would be appreciated. Thanks Doctor.
18 Responses
74076 tn?1189759432
Hi Brian,

1. You mentioned NSVT feels exactly the same as SVT in most people, I've heard SVT described as just fast but regular, can it feel irregular, like a rhythm thats "stuck"?

I should clarify that statement, it is a bit confusing.  NSVT by definition is nonsustained, by definition less than 30 seconds.  It is important to say that 99% of the people we see with NSVT have only 3-8 beats of VT lasting less than 2-3 seconds.  Most SVTs are also short runs of 3-10 beats, but a sustained SVT is much more common.  If your symptoms are fleeting lasting only seconds, I doubt you could tell the difference between the two.  If it is sustained, they would also feel similar but very different from nonsustained.

SVT is usually very steady and regular, that is unless it is atrial fibrillation.



2. The NSVT episodes I feel I had were within a month or so and haven't occurred since in about 7 months. Could they have been triggered by outside factors at the time of the occurrences such as too much caffeine, smoking, being overweight and eating poorly? Or do those factors simply aggravate an underlying condition?

If it was a reentrant rhythm like most SVTs, the underlying substrate has to exist before you can have it, although stress and caffeine certainly can help that along.  SVTs and panic attacks are very similar and can occur like this as well.

3. If they were caused by any of those factors alone, if I were to change those habits, is it likely they may never happen again or if a person experiences NSVT are they more likely prone to more occurrences over their lifetime?

If you experienced it once (SVT or panic attack), it is possible for this to happen again. The key is to find the underlying trigger if one exists (sleep deprivation, stress). There is no way to know for sure.

4. Being that they were isolated to that time frame, does that point to outside factors as the possible cause?

It may, but it is difficult to prove unless the same set of aggravating circumstances happened again.

5. Whats to keep NSVT from continuing into VT in a healthy, normal heart?

I have never seen or heard of that happening with a normal heart.

6. What regulates a rhythm like bigeminy or trigeminy as opposed to just having random frequent PVC's?

There is no way to know for sure.  It could be reentrant, increased excitability of the heart cells, something called triggered activity.  We don
Avatar universal
Hi, Brian72,

I have actually caught on a monitor a 13-beat run of what the docs originally thought was a NSVT but now are almost 100% sure (because of P-wave retrograde - which I don't understand the meaning of at all - if someone out there knows, I'd love an explanation) was actually SVT with aberrancy. According to my 2 cardios that I've seen, NSVT and SVT feel the same - no way to tell one from the other just by sensation. Once, when I felt an "irregular" tachycardia(the beats seemed to have irregular spacing between them), the doctor surmised that it probably was a short bout of bigeminy w/ my PVCs (on "bad" days, I get about 200 PVCs - very rare bigeminy).

I have heard that you can usually stop or slow an SVT with the valsalva maneuver (bearing down like you're having a bowel movement), but that an NSVT will not slow or stop from that. My cardio has assured me that an NSVT in a structurally normal heart will VERY rarely become sustained, and will almost NEVER become V-fib. I can sense your anxiety, and that's the hardest part for me. On anxious days, I am so hyper-aware of my heart, I can convince myself that the next irregular beat is going to be a death sentence. On days when I'm feeling good and feel that I can power through these, the blips hardly affect me. Like many, many, many doctors and people on this forum have assured us, in a structurally normal heart, these things (yes, including NSVT) are a mere nuisance. Easier said than done, I know (trust me, I know - I'm still in therapy), but you will live a long time, even with an occasional VT thrown into your days! I think the hardest part is getting over the anticipation of "what's next?"

In addition, my doctor told me that NSVT CAN be caused by anxiety. AND, he explained that there are LOTS of people in the world who have NSVT but don't even feel it (as there are people with PVCs. It's only sinister (according to my docs) in someone who is post-heart attack.

Looking forward to the doc's response. Feel free to email me at ***@**** if you have any other questions.

Dyan
Avatar universal
When you say NSVT feels just like SVT, by SVT do you also mean sinus tachycardia? I know that sinus tachy is a type of SVT, but usually by SVT we mean the tachycardias arising in the atria. If they all feel the same, I guess the only difference between sinus tachy and the other types is that the former can last for hours, whereas the latter should only last a few seconds, or they would become sustained. Is that correct?
Thanks!

Fran
Avatar universal
I thought SVT meant Supra Ventricular Tachychardia???
Avatar universal
My understanding is that sinus tach means that the heart is in a normal sinus rhythm - atrium then ventricle, and so on. SVT means that a preexcitation beat in the atrium suddenly creates a very fast rhythm in which the heart isn't "resetting" to its normal rhythm - the AV node isn't regulating the beat - some other errant pathway is. Sinus tach is what we're in when we're exercising, but SVT is an irregular rhythm where it's almost like the ventricles are trying to "keep up" with the atrium. Again, that's just my understanding. Not sure if that helps.
Avatar universal
When I have had SVT and NSVT they feel totally different. Svt feels like very fast sometimes even faint not really strong. But the NSVT when I have had it feels like a pvc but with many in a row it doesnt feel like its going fast when it actually is. THUD....THUD....THUD....THUD.... AND SO ON. I also feel the pause. Its a very terrible feeling. They feel strong and slow. The 26beat run I had (was recorded) felt like THUD WITH A VERY LONG PAUSE AND THUD AGAIN. Hope that helps.
Hope you all have a good heart day.
wmac
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