If adenosine worked, you probably had a so-called "AV Nodal Reentry Tachycardia" (AVNRT). That's the most common supraventricular tachycardia in young healthy people.
I can tell you what's happening.
Heart beats are (roughly) conducted from sinus node -> atrial tissue -> AV node -> His bundle -> ventricular tissue. On the way from atrias to ventricles, the beat is slowed in the AV node, to allow the atrias to beat, filling the ventricles extra, before the blood is pumped out in the body and lungs from left and right ventricle.
It works just like a hourglass (though a bit faster). The AV node is the delay in the middle.
Most of us are born with several "tracts" through the AV node. Most of the time, those tracts conducts electricity equally fast. And more important, they are able to conduct electricity again equally fast.
Sometimes there is an imbalance that makes one of the tracts conduct slower or faster, or we are born with a slow and a fast pathway. This is usually not a problem, but at times, a so-called PAC (premature atrial complex), extrasystole, that we all have some of during a day, is conducted through one of the pathways while the other one is still out of function. When the impulse is conducted through there, the other one is ready to conduct, and so on. You will get a "loop" (reentry) around the AV node which will only be broken by another PAC or temporary slowed AV conduction (vagus nerve stimulation or adenosine).
Less caffeine makes the heart less irritable; less PACs and less likely that they will trigger the SVT.
I don't think there are any MD's present here. If you need professional advice here, you need to ask your question in the Heart Disease (not rhythm) Expert Forum.
Good luck, take care :)
Your story could have been mine that is exactly how mine started!
I was sitting at my desk and my heart started pounding out of my chest, I went to the hosptial and heart was fine when they first hooked me up and then my heart rate skyrocketed!!! Gave me 2 doses of adenosine and my heart rate came down.
I never had issues with my heart before that (13years ago).
Thanks for your responses. I guess I'm just really curious as to why it happened out of nowhere without any change to my routine, but from reading the boards here it seems that just the way it is. I am seeing a cardiologist next week to find out if I need to do anything further.
@kc0409 - after your first episode, how often do you experience SVT? I'm worried that the fear that I'm going to have a repear is probably the worst thing about this, since it's not particularly dangerous in and of itself...
From what I have found out through my doctor when telling him that I have SVT, it's actually nothing to worry about. When it has happened to me, it has happened completely out of no where and while doing really different things so its not as if there is a typical thing that I do that sets it off. Also, I still drink coffee and still drink alcohol socially :) Don't be afraid because there is nothing environmental that makes it happen.
Also - when I went into the hospital (for the first time after years of it happening without knowing what it was), they showed me ways to make it stop on my own. They told me that unless it was abnormal from the other times it's happened, I don't have to go to the hospital unless I wanted to. They got me to 'bare down' which is basically squeezing like you're going to go poo (I know, weird and gross but after a few tries it stopped). If that doesn't work, you can try to pop your ears like you do on a plane (by holding your nose and closing your mouth and trying to blow..). They said that if that doesnt work, they can give me a needle to make it stop.
I also actually just talked to my family doctor about this last night and he said that if it because a problem in my every day life or if it interferes with my life, I can take medication that will make my heart rate have a max that it can beat. Also, if it's the circular path SVT (sorry, don't know technical terms), then they can have someone go in and caughterize (sp?) the path so that it doesnt happen, but that they don't typically do this procedure anymore in case it causes another problem.
I typically have my 'heart things' anywhere from once a year to once every couple years. Trust me, I know how scary it is but the most important thing is to realize that you're okay - try the different tactics to try to make it stop, and just lie down and relax. If you have any other questions please let me know!!
@ emma2727272: Thanks so much for your words of encouragement! Never having had anything like this happen before, it's just scary and, well, strange. I feel better having read all of the boards here.
I have never had to go to the hospital after that one episode of it but, I just had an implantable cardia monitor installed on Jan5 because of feeling like I am going to pass out they think it may be related to the SVT. They have talked about an ablation but not ready just yet.
I have short runs of it that last maybe 2 minutes. I started having panic attacks after my first run of SVT. It is a very scary feeling but I am one of the fortunate ones that I have not had any real long runs of it.
Just like you it literally happened out of nowhere. I was doing the same thing that I did everyday!!!!
I hope you get some relief from the "passing out" feeling. My first Cardiologist appointment is Tuesday, so we'll see what she says.
Thanks again for all of your responses.
I was diagnosed with PSVT back in December after having episodes like yours for nearly 20 years. Every family practicioner, gyn, & ob that ever went to basically had the same reaction....."Oh, that's very common in women....it's nothing to worry about" I had talked to many women over the years and NONE of them had these attacks. Like your attack, mine were just out of no where and as many times as I had them over the years I could never trace back to anything that I was doing to cause them. When I finally was referred to an Electrophysiologist (Cardiologist that specializes in the electrical system of the heart) I hear that for many of us they never figure out what the trigger is and find that it's more effective to try to control the symptoms. My understanding in that your choices are medication (a beta blocker or calcium channel blocker or combination of both) or a procedure called ablation. Most side effects are the same for all types of the "blockers" listed. I am on Metoprolol Tartrate and Verapamil. I recommend you look these up just so you have the knowledge about the meds before having to make a decision. My Dr. only recommended the surgical procedure in the event that the meds did not work.
Good luck at your appt. tomorrow. Let us know what happens.
Thanks for the luck! I went to the cardiologist today and I'm wearing a heart monitor for the next 24 hours to make sure nothing is going on outside of the SVT episode. I'll have an echo on Thursday to double check and if nothing turns up, my doctor advised me to just go about my business. She said that she doesn't recommend going on medication for one incident and I'm very happy with that. So, I guess, unless something turns up on the monitor or the echo, I'm just going to try to move on.
I'll let you know what happens.