Sorry to pull this post up.. I don't know how I found it but I think this is a case of a rare, but often forgotten supraventricular tachycardia known as "sinus node reentry tachycardia" :)
It is a sinus tachycardia that starts and stops instantly (just like other SVTs), caused by a reentry circuit near the sinus node. It can't be differed from sinus tachycardia without seeing the start and stop. Something people can mention to their doctors if they only blame anxiety?
The rate is usually 120-150 bpm and completely regular.
glad to have been of a little help, Adam. Yes, I think it's very wise to educate yourself as much as possible before meeting with any doc - that way you don't waste time with him having to explain the simpler stuff and you can get right to the more complicated stuff.
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sorry, you must have noticed that I'd misstated Bazett's formula
Bazett: QTc = QT/√RR
so from your first trace, that'd be .255 / √.539 = ~.38
and
.267 / √.406 = ~.42
from wikipedia:
"Normal values for the QT interval are between 0.30 and 0.44"
so that means you have a normal QT. Would you agree?
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as far as narrow QRS, I see this:
http://www.uptodate.com/patients/content/topic.do?topicKey=~l0czQKjH4jUUhP1
which says that <120ms is narrow, and likely is an SVT in origin. You measured 50ms, so it seems you have a narrow QRS.
Again, we see on that page the possibility of Paroxysmal SVT due to AVNRT - but other possibilities are listed there, too.
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I do see what you're saying are U waves in your 3rd trace. From the little I've read, they could mean a lot of different things.
How about if you measure ST length, as maybe a better indication of hypercalcemia. Also look for a long T wave.
Btw, it's possible that your hypercalcemia causes the putative PACs that start and stop your runs of (putative) PSVT.
Also, I see similar possible U waves in your other traces, yes.
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I'd definitely reinforce the idea of hypercalcemia and your MEN1 with the cardio. Btw, what are your serum Ca levels?
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There's also that strange wave in trace 2, at 1.03.5 that ends the tach run. It's like a short R. I'd guess maybe there's a negative wave occurring in conjunction there, and that reduces the R amplitude? Just a guess.
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Btw, your ambulatory event monitor has one lead. What view on a 12-lead would you think that view corresponds to? Maybe precordial V4? Or V2?
It occurs to me that you could change the places where you attach your electrodes to simulate any view that you want. Let's say that you wanted to look for PACs, you could find out what 12-lead view is best to see PACs, then attach your leads to simulate that.
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Have you thought of taking extra potassium to see if that reduces the tach runs? Maybe K or even Mg might help.
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HTH :)
Thanks so much...you rock! I really was just look for a "second" opinion before the first opinion. This is more just an inquiry of curiosity before I meet with the cardiologist.
In another ECG I took today, the R-R interval was 0.539 seconds and a QRS complex was conservatively 0.05 seconds. I was a little confused by Bazett's formula, so maybe you could take a look for me?
I also noticed some tiny U waves...small, but noticeable...which I believe are also consistent with hypercalcemia. If I get a chance, I'll also add a picture of it to my ECG page.
Do you think I should at least bring up the possibility of hypercalcemia to the cardiologist, or do you think that will be something he will have already considered?
Thanks again for your incredible insight! :)
Adam
sounds like it might be fun, Adam - as long as everybody knows it's only as a mental exercise. Real ECG reading seems to be a rather complicated and serious business.
That said, jumping right in as an amateur: the first thing that stands out in the 1st strip is that the run of faster tachycardia seems to end abruptly at about 26.5 seconds. Another is that the QRS seems narrow. Can you measure that duration? Since the norm for QRS duration varies with rate (gets shorter as heart rate gets faster), do you have the formula to give a corrected figure? (IIRC you divide QRS by the square root of the R-R interval... Bazett's formula)
Next, it seems to be a sinus tachycardia, since there's a P wave for every QRS complex.
Since the tach apparently starts and stops abruptly, I look for a comparison trace of Paroxysmal Supraventricular Tachycardia (PSVT) and find one at:
http://library.med.utah.edu/kw/ecg/ecg_outline/Lesson5/supra.html#paroxysmal
...which says that PSVT is usually narrow-QRS. The subtype referred to as AV Nodal Reentrant Tachycardia (AVNRT) is said to be the most common form of PSVT.
The javascript popup shows the PAC that starts the PSVT. So, if we look at your trace, there is that unusual squiggle which occurs right after the T wave at ~26.5... and after that is when the rate suddenly decreases. Is that squiggle a PAC? I don't know. Does a run of PSVT typically *end* with a PAC? I don't know. Seems like a start, though.
A narrow QRS is also said to be a feature of hypercalcemia, so investigating what other features there might be could be the next step. I think short QT might be another feature, but maybe somewhere I'd read about ST elevation - which seemed surprising
Any corrections, anybody?
Btw, clever idea using Audacity - and good of you to explain your method, too. Have you thought of using GIMP to add grids? That's not really necessary, though.
When this ECG was taken, I was sitting in a restaurant and hadn't moved from my seat for about 20 minutes. I am also going to post another ECG that I recently took if you want to take a look at it. In the second one, I had been sitting on the sofa for an hour.
Thanks again for your help!
Doesn't look overly abnormal, but I'm not qualified to say. Some variation in heart rate is normal and healthy.... of course you are tachycardic but this ecg is not in context, for all I know you could have just run up a flight of stairs. It has a normal PQRST though.... and looks ok...... but I am no expert! See a doctor please!!!!!!!!!!!!! I repeat, I have no medical knowledge at all, this is my disclaimer, see your doc for proper advice! :-)
Good luck!
Your are a little too advanced for most of us. Few of us, including me, are not qualified to look at an ekg and comment, so I'm not even looking at the link you provided.
From you family history it sounds like you need to carefully watch you hart condition and be, as it seems you are, careful about living a "healthy heart" life style. That said, AFib is not a "big deal", but it is more so if one has it at your age. My onset of AFib came in my mid 50s, and went full time (permanent) when I was 67, so for me it isn't a big deal, lots of us old folks have AFib. I'm still treating and working to get back in NSR, but that is far from a sure thing.
I'm sure your doctor will enjoy discussing with you the results of your monitor record:).