Avatar universal

? About svt

Hello y'all:) i was wondering if when you have svt episodes if your heart rate has a max as to how high it goes? For example, my highest heartrate has been up to 140 bpm...will it go higher? I know, its a funny question but someone else had made a comment about it so i was wondering if it was true. Thanks so much!
9 Responses
1464004 tn?1384135733
Not a funny question at all! Yours is a relatively low rate. Most of us with SVT on here clock in at about 220 BPM. My PSVT  usually comes in around that. Have you just been recently diagnosed?
Avatar universal
Yes newly diagnosed:)
Avatar universal
My SVT/AVNRT, for extended periods, 1-4 hours, was 144 bpm max; and as low as 128 bpm.  My EP diagnosed mine on EKG at only 128 bpm.  But, I saw, during another event, 190-210 bpm for 1-2 minutes, and one other event at about 228 for 1-2 minutes.
1423357 tn?1511085442
The longer I'm associated with this group, the more things I learn. In my 54 years of dealing with an AVRT form of SVT, my heart rate during these thousands of events was relatively uniform.  My rate as an adult was typically 220.  It could be a little higher if I was under physical and respirational stress; around 240 as what would be experienced during my cycling or speed skating activities.  As a young kid of 6, it was recorded in a hospital at 312bpm.  As an adult, I could be at a restaurant, watching TV, driving home from work when it would start.  The rate was always rock stable at 220bpm at normal respiration.  AVRT is an accessory pathway not associated with AV Node.  It's nothing more than an errant strand of conductive muscle tissue that shouldn't be there and perhaps this leads to consistent SVT rates.

AVNRT is NOT an accessory path SVT. AVNRT occurs when a reentry circuit forms within or just adjacent to the AV node. These circuits, or pathways are formed from tissue that behaves very much like the AV node, and some physicians regard them as part of the AV node.  Perhaps this form of SVT lends itself to varying rates.

As someone above me mentioned, 140bpm is on the very low end of people who experience SVT. AVNRT is four times more common than AVRT, so the odds favor that.  I'm also under the impression that unless you have Wolff-Parkinson-White Syndrome, it is difficult to actually ascertain which form of SVT you have based on EKG alone.  My electrophysiologist saw nothing on my EKG prior to going in, and assumed it was AVNRT,  It wasn't until he got in there that he found a wide accessory path in the left atria that was extremely touchy and conducted very easily and very efficiently.  Subsequent ablation prevented conduction, and I was cured of 54 years of it.
1807132 tn?1318743597
My understanding is that AVNRT is an accessory pathway svt it is just that the extra pathway is leading into the avnode as opposed to some other place in the heart.  Obviously if everyone had this extra pathway, meaning it is normal anatomy for the heart, then everyone would get avnrt, which isn't the case.  But avnrt is due to having extra muscle tissue that acts as a pathway into the avnode.  Where other svts, like PATS is due to a run of pacs or afib but maybe I am mistaken.
Avatar universal
Would they be able to tell from my holter or ekg's if i had WPW?
1423357 tn?1511085442
WPW quite often shows a number of clues:

-a delta wave slur on the upstroke of the R or on the downstroke of an S wave or delta wave

-a prolonged QRS complex (>0.10 seconds)

-A shortened PR interval (< 0.12 sec)

The waveform though is primarily the clue.  Interestingly, my EKG showed this faintly, but it turned out to be another form of AVRT.

1423357 tn?1511085442
I sort of answered your question indirectly, and I apologize.  I don't know if a Holter would show this.  I forget how many angles they record.  I would think that a full lead EKG in physician's office while in a still, prone position would be best.
1423357 tn?1511085442
... keep coming up with additional comments....

People with AVNRT have two pathways within the AV node:
The slow pathway (alpha):  a slowly-conducting pathway with a short refractory period.
The fast pathway (beta):  a rapidly-conducting pathway with a long refractory period.
During sinus rhythm, electrical impulses travel down both pathways simultaneously. The impulse transmitted down the fast pathway enters the distal end of the slow pathway and the two impulses cancel each other out.  However, if a premature atrial contraction (PAC) arrives while the fast pathway is still refractory, the electrical impulse will be directed solely down the slow pathway. By the time the premature impulse reaches the end of the slow pathway, the fast pathway is no longer refractory, hence the impulse is permitted to recycle up the fast pathway.  This creates an impulse which continually cycles around the two pathways, activating the Bundle of His.. The short cycle length is responsible for the rapid heart rate.

AVRT is different.  It involves the pre-excitation of a congenital accessory pathway causing early activation of the ventricles due to impulses bypassing the AV node via an accessory pathway.  Accessory pathways, also known as bypass tracts, are abnormal conduction pathways formed during cardiac development and can exist in a variety of locations and in some patients there may be multiple pathways.

There is an excellent online resource, lifeinthefastlane(dot)com which explains SVT in detail, but in layman's language.
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1807132 tn?1318743597
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