Prlonged Qt / Qtc interval

I am a 48 year old female and was diagnosed with Atrial tachycardia in January 2011.  I had an EPS study with ablation done due to frequent PVC's that I was having when my TSH level was supressed (dx thryoid cancer in Jan 2010 with TT in Feb 2010).  Ablation had to be aborted after five hours due to fact that arrhythmia is in a spot (His bundle) that when ablation was attempted, I was at risk of AV Node block, thus possibly requiring a pacemaker. I was put back on Flecanide but had to switch Rythmol due to bad side effects.  The Rythmol has been pretty good at controlling the tachycardia (still have PVC's).  In April, my Qtc interval was just above normal (490) but EP dr said nothing to worry about.  At my visit last week, my Qt / Qtc was 563 / 640 (or close to it).  I had to wear a holter monitor but did not get results back yet.  I am wondering if these numbers are getting dangerously prolonged and if I should be more persistant in getting answers.  I do not know how long it takes for dr to get results but assumed if this was an issue, he would have contacted me by now (handed in monitor on Friday)

Just wondering if someone could advise if this is something I should worry about or not.  EP dr did say he was a little worried as I have also been feeling dizzy and lightheaded the past few weeks.  I did pass out once but recovered quickly as I feel this was because I got up to fast.  

Any feedback would be greatly appreciated.  I see my cardio dr tomorrow for another ekg (currently off synthriod for RAI treatment) so I am monitored weekly.  Hopefully result will improve and last week was just and oddity.

[is_something_wrong]

At QTc 640 with QT 563 msec, your heart rate is approx. 77.

Your QT is far too long. The most important question is; did your EP doctor see this EKG? If not, tell him immediately. I can't say if the numbers are "dangerous" or not, it depends on a lot of factors than an EP can determine. I'm not a doctor, but in general, QTc above 600 msec with PVCs seems bad to me.

It also seems you may have misunderstood your diagnosis. If the tachycardia did origin from the His bundle, you don't have atrial tachycardia; the His bundle isn't located in the atrium, it's located in the ventricle. An arrhythmia that origin here isn't named "ventricular tachycardia" so you can relax, but it's referred to as "junctional tachycardia" because the His bundle is a part of the AV conduction system.

I would talk to the EP doctor as soon as possible regarding the prolonged QT interval.

[BLT812]

It was the EP dr who read the ekg while I was in his office.   He requested that I wear a holter monitor for 24 hours but haven't gotten results back yet.  I am assuming no news is good news.  Today, I went to my cardio's office for my weekly ekg and QT / QTc intervals was within normal limits.  Can QT / QTc intervals be prolonged one time and normal the next time?  I have had three prolonged intervals in the past 6 months but also several normal ones.  Todays results noted "possible anterior infract" for which I have not idea what that means.  Cardio dr was not in office so I could not talk to him.  Not sure if I should follow up with him, or this is just an insignifcant finding.  I hear Ekgs are very senstive and need a human review as well.

[stevie_wonder]

I would DEMAND answers immediately. A QTc over 600 is extremely dangerous. So many doctors overlook prolonged QTs that it enrages me!
Get another opinion if this doctor avoids the issue.
Take care,

[stevie_wonder]

Another thing I forgot to add is that QTc can change very quickly and often do throughout the day depending on many different things.

[BLT812]

Thanks.  I have put in a call to both my EP dr and my cardio dr to discuss results of both the prolongation of the QTc and the ecg notation of "possible anterior infraction".  I have no idea what that means and I want to understand fully.  Will keep you posted.