SVT/IST

33 year old female. Episodes of racing heart for quite some time now. After wearing Event Monitor Cardio said I have SVT.(heart rate of 152 while in bed)  Gave me 25 mg of metoprolol. I decided to go see an EP for his opinion. He looked at event recordings and said he doesn't think SVT, but sinus tachy.  Would that then be IST?  He told me to stop metoprolol because I have asthma. I stopped that Saturday..by Monday my heart is racing all the time and I had another bad episode last night of the tachy.  Would this get worse from stopped bb, even though I was only on it for 2 1/2 weeks?  EP wants me off all medication so he can have me wear a holter.   Then he said he'd probably prescribe a cardizem.  I have a hard time believing these episodes are sinus tach.  Even the print out on the event recording says "narrow complex tachy".  I don't know why ep thinks it's not SVT?  My follow up after the holter is not until Dec 11th...do you think I'll be okay with no meds all that time? I feel like I'm going crazy.  Heart races just to walk across the room.  Would love your opinons!  Thanks!

Charity

[Michael J. McWilliams, M.D.]

Would that then be IST?

Inappropriate sinus tachycardia is more of a chronic condition.  If this is all new, it is not inappropriate sinus tachycardia.  A holter monitor will give an average heart rate for 24 hours.  If your average heart rate is over 100 bpm and stays that way for months and other lab tests are normal (thyroid), it is probably inappropriate sinus tachycardia.

Isolated episodes of fast hearts rates are other SVT or anxiety/panic attacks.


Would this get worse from stopped bb, even though I was only on it for 2 1/2 weeks?

It is unlikely but possible that you could have some rebound faster heart rates from stopping the metoprolol.  If patients are worried about that, I will often wean them off by having them take half their previous dose for a week or so.  You will probably tolerate coming off metop without a problem.

I don't know why ep thinks it's not SVT?  

Hard to answer that one without seeing the strips.

My follow up after the holter is not until Dec 11th...do you think I'll be okay with no meds all that time?

SVTs are almost never dangerous rhythms and if it is sinus tachycardia, you should be fine off medications for that long.

If it is sinus tachycardia, I will often recommend medications for anxiety like paxil/zoloft, just to see if it helps.

Hope this answers  your questions.  Good luck.

[sugarpea013]

Hey there, I just wanted to offer some sympathy. :-) I have IST and it was not a pretty road getting to that diagnosis. I was thought to have had SVT, in fact 3 different cardiologists termed it that. However I went in to do an EP study and the electrophysiolgist knew right away it was sinus tachy. They are very good at what they do, and are extremely specialized at reading rhythms. I wish you the best of luck in figuring out what it is that ails you.