Erratic HR following EP lab study, despite no ablation?

[Chip8]

One week ago I had a catheter procedure with the objective of inducing SVT/AVNRT so that an accessory electrical pathway could be ablated.  But, the inducement was not successful.  My EP said that he could only induce about 7 consecutive beats of SVT and that it was not a long enough run so that he could map the location.  He said that he did not burn/ablate anything.  My SVT/AVNRT had been previously diagnosed on EKG, during a 4 hour prolonged high heart rate.

Today, during light exercise, I experienced several runs of very high heart rates in the 190-210 bpm range.  This was much higher and frequent than any SVT which I had experienced prior to last weeks heart catheter/EP lab study.  I was surprised that my heart seems much jumpier now, despite no ablation (burning) having been done last week.  My EP started me on Flecainide following last week's procedure.  Flecainide is used to prevent and treat tachyarrhythmias.  I have read on this forum that it can take several months for a heart to calm down following an ablation/burning procedure.  But, I didn't have any ablating(burning).  Can the heart catheter/EP lab study cause more erratic heart beats when no ablation was done?  I sincerely appreciate anyone's input.

[Chip8]

Tom, I'm happy to hear that your procedure has produced such effective results.   My SVT is relatively minor compared to those very high HRs you experienced & also the way it limited your skating when you were competing at such a high level.  I've been only a local "trophy hound" for the past 35 years, but I live to be active and will never settle for the alternative.   I haven't given up and will keep pursuing this with hopes for a cure.

[Chip8]

Thanks for your comment.  The EP's nurse actually used the term, "right side".  The same morning and prior to the recent EP lab study, she said, "since yours is in the right atrium (as opposed to the left), you will not need a blood thinner and therefore, will not have to stay overnight in the hospital".  And, the EP said to me, following the procedure, that your  AVNRT is near the A/V node.  I don't know how he knew that for certain as he could not induce SVT.  He first diagnosed AVNRT, based on the EKG which captured a 2 hour SVT event, about 6 months ago (HR was only a constant 128 bpm during that one- seems very low for AVNRT, as others have commented here.)

[Bromley]

Hi. 3rd opinion!!!  AVNRT occurs in small area in the center of the heart. I dont see how they could call it  "right sided". You might check whether that is AVRT instead of AVNRT.  This can occur left side, right side, or both, and is often associated with an accessory pathway. AVNRT is associated with fast and slow pathways, near the av node.

[tom_h]

Mine first started at 6 years of age.  The rate at that time was clocked in the hospital at 312 bpm.  It was ablated as I approached 60.

I was under general anesthesia and partially intubated.  The shot of Vallium they gave me in the short stay cube before rolling me down to the lab made me so groggy that I had a hard time scooting from the bed to the table.  I was awake long enough to remember them propping my arms up comfortably.  That was it.  Yet, my electrophysiologist said I was a dream patient as I went into SVT merely by touching the catheter against my heart wall.  So as you can see, it varies greatly from patient to patient.

[MichelleP_3811]

I really suspect that the twilight sedation may have been too much especially if you only notice these during times of exercise.  For your knowledge what you stated does sound like classic accessory pathway svt, the pause from the ectopic beat, a pac or pvc, allows the signal on the extra pathway to complete a loop that then sustains itself until it is disrupted again which can be from another ectopic beat that you can try and trigger by drinking very cold water or the bearing down like I spoke of.  Really try one of those if you notice an episode flare up on you.  Anyways, I had a colonoscopy once and I was totally out but was not out at all for the ablation.  I probably could have fallen asleep but the adrenaline would have likely woken me up.  You may want to try again and not be so sedated if possible.  After all my terror about doing it, it really wasn't scary at all.  The only difficulty was when they ablated that hurt a bit but otherwise it really was like getting ivs put in and then they raced your heart but that isn't anything we haven't experienced.  Anyways, it is likely your heart is a bit wound up and throwing more ectopic beats and subsequently throwing you into more svt episodes.  They can feed off each other unfortunately but if you maybe give yourself a bit of a break it may help your heart settle down.  Though too bad this couldn't be happening while you were in the study.  Such is life unfortunately.  But hope is not lost.  I suspect you can get a cure one day they just have to adjust how they handle you.  Each of us is different.  

I will say avnrt or any accessory pathway svt is not just an older person's problem.  It is actually a younger person's problem as it usually presents by 20 though it is not unheard of to present later.  Mine I have had ever since I can remember.  The thing is though the ep may be more use to doing ablations for afib and not avnrt and so that inexperience could be a factor though mine also made a comment about his patients all being over weight.  So I guess as much as we feel like there are a lot of us with accessory pathway svt for an EP maybe there aren't as many for them as one would think.  Take care.

[tom_h]

What you're describing, Chip is classic "SVT", whether it be AVRT or AVNRT, it usually starts and stops on a dime.  The conversion back to NSR is instantaneous, but may ramp down from the low 100';s usually because you're amped up a little from the event.  I awoke from my procedure with a HR of 135.  I remember seeing it on the monitor.  But I was also in NSR with the electrophysiologist peering into my eyes with a thumbs up.  The high HR was attributed to the latent effects of adrenaline which was administered as well the 17 burns I received.

I experienced this "mayhem" as you accurately describe for 54 years.  Now imagine trying to compete at world class levels in sprint cycling and speed skating with the prospect of that happening  constantly in the back of your mind, and you'd get my life.... or what was!...... Now I'm to darn old for it to matter much........

[Chip8]

I think my EP is excellent in many respects and I like him.  But, I don't think that he sees many patients, similar to me, who exercise intensely, frequently, and for many years.  Most of his patients appear to be 15-20 years older than me and most are over-weight- at least the ones I see.  Perhaps, that could be one factor for an incorrect diagnosis- AVNRT.  He doesn't seem to understand or relate to intense exercise.  He only suggests walking.

[Chip8]

I was sound asleep during the procedure and felt calm before it.  They said to me that they used the same type drug for sedation, often used during a colonoscopy.  I felt or remember nothing during my EP lab study.  I only remember waking up very quickly, after the procedure, as I felt my heart beating very rapidly.  I wasn't groggy/sleepy- all of a sudden I was wide awake.

In response to your question: "Can I ask when you have an episode does it feel like it starts and stops in one beat or does it ramp up and down more slowly?"  
...It feels like it stops and starts quickly, in about one beat.  When it starts, I sometimes see my Polar HRM display show 0 briefly and I can also feel a skip in my heart.  Next and immediately,  (this morning) I saw a HR in the upper 190's and stay at that level for 1-2 minutes.  Then, suddenly, my HRM displayed low 100's and continued slowly dropping to normal levels as I was walking at that point.  I wasn't light-headed or dizzy at all, nor short of breath while walking.  But, I was definitely short of breath during the 190's HR.

I do have a low resting HR of about 45-50.  My EP said I am very fit for my age, so perhaps that may be the explanation for the prolonged high HRs in the 150 bpm range for AVNRT.  Assuming it is, in fact, AVNRT.  ??

I will follow your advice and rest a few days, without exercise.  I probably have a tendency to do too much, too soon.  If these extremely high HRs continue next week, I will ask my EP or perhaps, get another opinion about it.   I could tolerate the 150 bpm prolonged high heart rates.  But, this 190-210 bpm stuff is mayhem!  Thanks again.

[tom_h]

Yes, I would agree.  In fact I think 150 is outside the window of what is the accepted range of 160 and up.  I hasten to add that this is the TYPICAL range.  In my experience here, there is plenty of atypical stuff happening here too!

I wanted to add in my last post that you are among only a few people in my 4 years associated with the forum that have had failed electrophysiology procedures for AVNRT.

It's pretty rare.  Most of the "problems" are people who initially had what they thought were successful ablations, but for some reason have had it reoccur.

[MichelleP_3811]

Hmm, that seems rather low for avnrt.  The pathway for avnrt is around the avnode so a very very small circle which usually creates a beat that is in the 200s not 150s.  My EP said there are other types of svt that circle the whole heart like wpw or maybe even avrt that do not involve the avnode that could present at the lower rate of 150 though I guess if you are well conditioned it could be a factor in the lower rate.  I have to assume your EP knows way more than me and was making a very educated guess that you had avnrt and since he said he was able to produce 7 beats of it I suspect maybe you were too sedated or have a really relaxed laid back nature to be too calm on the sedation to produce your issue.  Were you awake for the procedure or did they put you out?

Can I ask when you have an episode does it feel like it starts and stops in one beat or does it ramp up and down more slowly?  Well for your frame of reference my heart rate was really elevated for at least 3 months past my ablation and I had a pretty high amount of ectopic activity for a couple of years.  I will never get rid of the ectopics but I kind of think my exercising did inhibit my recovery so maybe slow up the exercising a bit and see if it helps.  Maybe even take a break for a week and slowly ramp back up.  Exercising is good but it is still strain on the heart and you have been through a lot and still are if you are getting the episodes.  Anyways, give your heart a bit of time to settle down then regroup about the ablation maybe seek a second opinion about your situation with another ep.  In general though it can be a bit elusive they generally are highly fixable you just got a bit of bad timing in my opinion or just too many meds.  

[Chip8]

Michelle, my SVT episodes, over the last year, were occurring about 3-4 times per week, only during or immediately after intense exercise.  I would experience a sudden increase in HR, about 20 beats higher and my breathing would become very labored and I usually had to stop my running or bicycle riding.  Usually this occurred at only about 150 bpm, but my HR would sometimes stay at that level for hours.  It is only since last weeks EP lab study that I've observed the very high 190-210 bpm on my heart rate monitor during and after exercise.  But, these are only brief periods, about 2 minutes or less,  per episode.  I do have to stop my activity when this happens.  So far, since last week's procedure, none of these high HR events have lasted longer than 1-2 minutes.  Prior to the procedure, they lasted about 1-4 hours, but at lower HR levels- about 150 bpm.

Thanks for the comments.

[MichelleP_3811]

There could be a few reasons why they were unable to produce an episode long enough to map from your condition being too infrequent to them sedating you too much.  I was pretty awake for most of mine and a lot of EPs prefer that because too much sedation can inhibit the adrenaline used to incite an episode.  Also you say they were more frequent but how frequent.  Mine were starting to happen at least biweekly or more.  I was pretty stressed out the week before my ablation so I was super active and the EP was able to induce an episode on the first try so if you only have them a few times a year that could be a factor.  I think like Tom said, no matter if they ablated or not they incite the heart and that is what has gotten your heart all worked up and unfortunately it can take a while to calm down.  It is also possible you are a bit jumpy from the meds but if you  aren't falling into svt then it is probably working but my EP actually didn't suggest any meds even if I never got my svt fixed.  Basically he stated they would not be able to stop the episodes only slow them down when they happened.  They happen or get triggered usually because of an errant extra beat called an ectopic.  Nothing is really available to prevent those so  we are always vulnerable to falling into svt because of them.  Yet slowing the heart rate down in general can actually cause some people to have more ectopic beats so it is possible the meds are creating a situation where you will have more episodes but at a lower rate.  Well anyways that is my take on it but I am not a doctor so I could be wrong but my doctor basically said, ablate or live with it.  So I would say evaluate how often you have episodes and if there was any excess in sedation that may have prevented a successful ablation and then may contemplate trying again in the future.  But so long as you are able to get the episodes to stop as soon as you can through Vaso Vagal maneuvers like bearing down and straining to go to the bathroom while holding your breath or drinking a really cold glass of water to name a few then technically the svt should not be a threat to you though but you have to go with your instincts what was right for you.  

[Chip8]

Tom, I've had similar symptoms of the prolonged high heart rates for many years.  I've seen it on my heart rate monitor during and immediately following intense exercise.  I just lived with it because I described it to many doctors, over many years, and they seemed unconcerned and didn't think it was serious.  My age is 56 and in recent years the events have become much more frequent.  I went to a Cardiologist, with no referral.  I should have done that many years ago.  My SVT was only diagnosed about 6 months ago.  I tried Verapamil, but that didn't help very much, if any.  My EP said that he confirmed my SVT is on the right side.  He said that about 6 months ago, following the EKG.  I assumed then it was a definitive diagnosis because the EKG automatically listed about 5 abnormal conditions and based on that EKG, my EP said AVNRT, on the right side.  He did not have to do a transseptal puncture.