high heart rate

[jenniferj]

I am a 31 year old female who is about 40 pounds overweight.   I run 1.5-2 miles everyday at about a 10 minute mile.  Back in April I had an episode of extreme tachycardia about 152 and this was while sitting down.   I also had some mild chest pressure but no shortness of breath and the pain was non-radiating.  I went to the ER and the had to give me labetalol to bring the heart rate down.  I had an echo which showed 51% EJ and mild diastolic dysfunction and a Cardiac MRI that showed some abnormal septal wall flattening.  My EKG also showed a right bundle branch block but was otherwise normal.   I was given a 48 hour holter monitor and sent home.   The holter monitor failed to capture anything and the cardiophysiologist was otherwise unimpressed with my symptoms and test  results.   He basically said to make another appt in a year to do another EKG and to lose some weight (I'm trying).   He also said that if this was a one time episode it was nothing to be concerned about.  Well I was good until about 4 weeks ago.   I had another episode of extreme tachycardia this time it was 164 after sitting in a bed for almost an hour.  I was extremely dizzy, nauseated and had chest pressure again.   The ER decided to give me anti-anxiety meds to see if that helped and it never even budged my heartrate, so they then had to give me labetalol again which only brought my heart rate into the 110's.  This time they sent me home with a 30-day event monitor.   I have had multiple episodes of tachycardia and bradycardia (my heart rate has occasionally been in the 50's even while standing) since wearing the monitor.  A few times they have had me do a recording while on the phone with them and then told me I could clear my monitor.  I have an appt in 2 weeks with the cardiologist.  They will have my monitor results and will assess at that time.  They have mentioned a Stress test and an EP study.  
First Question: why would the event monitoring company have me do a recording while on the phone with them?
Second Question: what will the stress test and EP study show?
Third Question: Any thoughts on what is causing my heart issues?????

[MichelleP_3811]

There are a few things it could be but it is possible you have an accessory pathway svt.  The biggest factor in this type of svt is that it starts and stops in what feels like one beat.  Have you noticed that?  Generally the heart rate is super high in the 200s but it isn't unheard of for it to be a bit slower depending on where the extra muscle tissue is.  It is a bit odd it would start in your 30s.  I had one called avnrt and had episodes ever since I could remember but it was only until my 40s when it got bad.  But it is possible the exercising you are doing to lose weight changed the structure of the heart a bit allowing some extra tissues to connect forming a loop.  The stress echo will evaluate the health of the heart while under duress of physical exercise.  If it is deemed capable of handling exertion and is structurally normal what you are experiencing is likely not a danger.  They would offer an EP study and ablation if they feel your issue is something that can be fixed.  Mine was caused by an extra muscle fiber leading into the avnode causing the signal to get caught in a loop.  It was easily fixable.  If it turns out to be something like afib that is a bit harder to treat with ablation but you first need a general idea if this is a fixable svt.  As for the monitor company requiring a second reading they need to know you are not in danger so they have you do a reading with them on the phone before they can release you to be on your way.  Obviously you were not in any danger with the secondary readings with them.  It is just a safety precaution.  So now it is really just a matter of waiting to hear what the doctor has to say and what your next steps are.  Until then try to drink lots of water.  It will help your heart function better.  Also considering your weight, are you diabetic?  Do you check your blood sugar regularly?  If so I would check it when you are having the issue to make sure you aren't experiencing a reaction to low blood sugar though that would likely have shown up while in the ER but but worth checking out.  Well hang in there.  I know waiting to find out what is going on is really hard.  Just try to keep your mind distracted and do keep us posted on how you are.  Take care.

[tom_h]

Here's my comment regarding the monitoring company having you do another recording "live" while they're on the phone:

If you send them a recording with a cardiac anomaly like SVT for instance, and the recording ends while you're still in SVT, they won't take your word that you're feeling fine.  They want to see proof that you're in normal sinus rhythm (NSR).  So they ask you to do a live recording and have you send it to them.  If they see nothing, then they're satisfied.

My lab made me do this.  I was in SVT when I made the recording, but had terminated it and was in NSR when I phoned it in.  When I balked at doing a recording, the tech said it was either that or an EMT would be knocking on my door.......... I sent the recording, and they were happy.

[jenniferj]

Gotcha!  I wondered if that was the issue as far as the recording company.  

Thank you both for your responses.  I am not diabetic and am sufficiently hydrated (they ran lots of blood work).  I also do not have a thyroid issue or anything like that.  In other words outside of being mildly overweight and the heart stuff I am healthy.  Also I don't drink caffeine and am not on any kind of medication so it isn't anything like that either.   My appt. is in 2 weeks.  We'll see what they say!  Thanks again

[jenniferj]

Ok just to update.
Met with the doctor this week and your were right Michelle.  They think I have an accessory pathway SVT.   They will be scheduling my EP study in a couple of weeks.  Thanks for the information!