a-fib vs. a.t

[mongo_jones]

at my icd interrogation in november the tech told me that the icd had caught 25 incidents of arrythmias since my previous interrogation and referred to them airily as a-fib. however, since none of the episodes were very long (the longest a minute) i didn't think too much about it. i'd posted about this here--as some of you might recall.

at the next interrogation, a couple of weeks ago, i decided to ask the tech (different guy) for details. so he pulled it up and lo and behold it turned out that i had had 25 episodes since the device was last cleared a year ago (NOT just since the interrogation prior to the november one) and that in fact almost all of these were instances of a-t, not a-fib. moreover, almost all of them were bunched together in a period of a few days in september.

the next time i see my cardiologist i'll ask about all this but i'm wondering if anyone here knows generally if a-t is generally something harmless or whether it is bad in its own right or if it can be a marker of things to possibly come?

thanks in advance!

[mongo_jones]

Re: a-fib vs. a.t

okay, so i did some quick research on the net and as far as i can tell atrial fibrillation is just a subset of atrial-tachycardia, which can encompass a range of arrhythmias. some sites seem to refer to these only as svt's--supra-ventricular tachycardias. so, it would appear that a.t by itself is a fairly meaningless description--true?

i guess what i need to find out is how the i.c.d distinguishes between a-fib and just a.t.

[Sarah]

Re: a-fib vs. a.t

super short arrhythmias 101

atria: top half of heart
ventricles: bottom half
arrhythmias can start from either place. atrial arrhythmias are typically less dangerous (lethal) than ventricular. ventricular arrhytmmias are considered risk factors for sudden death or can cause it straight up.

tachycardia just means a rate over 100 that is starting from the top half of the heart. most types of at are harmless (in that you aren't going to die suddenly) but obviously you don't want to have it all the time or for very long periods of time. supra-ventricular is the long way of saying atrial. it isn't entirely meaningless -it just all means your heart was beating really fast.

fibrillation, however, is a whole other ball of wax. fibrillation means that the beats are not regular --they are random. this causes reduced output, reduced efficiency and thus, reduced energy. tachycardia, by definition, is regular but super fast. fibrillation is usually faster than normal but doesn't have to be. fibrillation as a definition ignores speed.

AF can cause strokes and heart attack, so it needs to be treated. if you were really having af, i think they would have done something about it.

AT should be treated as well, but medication usually wipes it out pretty neatly. AF can be tricky.

hope this helps.

s

[Linda]

Re: a-fib vs. a.t

Atrial tach, as Sarah explained, is a rate faster than 100, but the EKG will show a "P" wave. This "P" wave represents the contraction of the atria and shows that the atria are actually pumping blood into the ventricles. It will usually be a regular rate as will the ventricular rate, one beat following each "P" wave. Atrial fib is a chaotic contraction of the muscle fibers in the atria and they are not contracting together, so no "P" wave is present on the EKG. This chaotic contraction doesn't effectively pump blood from the atria to the ventricles, so you have the pooling of blood in the atria which can then clot and possibly break loose causing a stroke. That and an irregular rate of contraction of the ventricles will be the distinguishing features that the ICD is looking for. In atrial fib, the atrial rate can reach a rate as fast as 700, so obviously, the cells aren't working together. That's when the ventricles do their own thing. Thank goodness for independent thinkers! Linda

[Lisa Salberg]

Re: a-fib vs. a.t

Linda and Sarah did a great job with this question!
Thanks Ladies!!!!!!!!!!!!!!

Lisa

[mongo_jones]

Re: a-fib vs. a.t

Atrial tach, as Sarah explained, is a rate faster than 100, but the EKG will show a "P" wave. This "P" wave represents the contraction of the atria and shows that the atria are actually pumping blood into the ventricles. It will usually be a regular rate as will the ventricular rate, one beat following each "P" wave. Atrial fib is a chaotic contraction of the muscle fibers in the atria and they are not contracting together, so no "P" wave is present on the EKG. This chaotic contraction doesn't effectively pump blood from the atria to the ventricles, so you have the pooling of blood in the atria which can then clot and possibly break loose causing a stroke. That and an irregular rate of contraction of the ventricles will be the distinguishing features that the ICD is looking for. In atrial fib, the atrial rate can reach a rate as fast as 700, so obviously, the cells aren't working together. That's when the ventricles do their own thing. Thank goodness for independent thinkers! Linda

so, is it safe for me to assume (until such time as my cardiologist suggests otherwise) that i should worry less about instances of brief a.t and more about instances of a-fib (should there be any)?

[Linda]

Re: a-fib vs. a.t

Well............ Don't assume anything, have the doc explain it. It would seem that your reasoning is probably correct but confirm with the doc to be sure. If it is A fib, you need to talk about it and just how often and how long it is lasting. Be sure it is addressed as an issue.

Just walking up a flight of steps can increase your heart rate to show an atrial tach. Your doc needs to tell you if this was what seemed to be an abrupt and sudden onset of tach (a potential for a prob) or a gradual onset indicating an increase in activity and a normal heart response. Lots of variables to look at. The other thing to remember is that the ICD is a computer that is programed by a human mind. It can only spit out info as good as the info fed into it. It doesn't get a little bit wiser with age and experience. It doesn't have the advantage of looking at the whole picture. When we do interrogations for my son, if an event print shows, we look at date and time and he can tell us if it was a time likely to have been very active, etc. For instance, last reading, we saw a nasty printout about midnight or later and assumed he was sleeping. After checking the calendar, he remembered he had been studying for finals and had gone to the cafeteria at that time, cold and windy outside, etc. So the event wasn't quite such a big deal after all.

Answers are rarely clear cut, so I hope this info at least helps a little. Best wishes and I hope you get your answers soon, Linda