Ok, so I am completely ignorant in this, but the "good" news, (sarcastic) is that, it appears.....not only does the ECG machine make mistakes computing this, but also 1/3 of the EPs, and also 3/4 of cardiologists. Now doesnt that make us all feel better.
" Further, a significant component of the score, namely the ECG index of cardiac repolarisation known as the QTc, can be computed erroneously by the ECG system or miscalculated by the physician performing his/her independent calculation. In fact, Viskin et al15 demonstrated that the QTc was calculated incorrectly (when compared with LQTS experts) by one-third of heart rhythm specialists and by nearly three-quarters of cardiologists. "
I used to have this info also but my pc died so I can't quite remember the parameters...
most of my QTC's have been around 400 and a couple above 450...one I see is 473 (most of mine are in my journal my personal heart page)
I think the skipping hearts website had some info about the intervals on EKG's which is very helpful so you may want to check there - I think that's where I got my info from...dont' quote me because my brain is as bad as my dead pc right now - I think 470 was a cut off which I just went over but for the life of me I can't remember what for. (maybe LQTS?)
I was told EKG's much like Echo's are only as good as the Tech and interpreter reading them...really makes me wonder.
have you thought about going to an internist? I was so shocked when I went to the one I'm seeing - he knew more about heart stuff than my cardiologist did and really has more training about the body overall...he did some deep skin biopsies that he thinks may help give me answers about what's going on in my system. If he can solve this puzzle when top notch EP's can't I'll buy him dinner =)
I have never heard that term, not sure what that is. If anyone solves your mystery I bet you do more than buy them dinner....probably knocked them over with all the excitement you will have lol Thanks for the info...
sorry do you mean internist? if so look up on your insurance or on doctor's profiles on a site like vitals . com and find someone in your area who is in Internal Medicine
Internists are sometimes referred to as the "doctor's doctor," because they are often called upon to act as consultants to other physicians to help solve puzzling diagnostic problems and spend at least 3 years extra learning how to prevent, diagnose, and treat diseases that affect adults.
luckily someone recommended I find one and recommended I not take Plaquenil with my heart problems that I had been given by the Rheumatologist
Funny you should mention the QT/QTc numbers. I have had stress tests, ekgs, echos for the last 20 years and noone every mentioned to me that my QTc number was high.
So last month, I was getting these fleeting pains in my upper stomach up to my chest. I really didn't think it was my heart but I called my cardiologist who was of course on vacation. Then I called my internist who was also on vacation. Ugh, so the office told me to go to urgent care just to make sure it wasn't my heart. Off I went. They ran an EKG. My heartrate was high (98) as I was nervous. I wasn't having a heart attack (which I knew), but the ekg for the first time stated possible left atrial enlargement; ST abnormality, possible digitalis effect.
So, I was at Scripps and because my cardiologist didn't work out of that hospital, they had nothing to compare my ekg to. I was told there were non specific changes (whatever that meant) and released to talk to my doctor the next day. The office called and said that everything was fine as they compared it to my existing ekg's etc. I then told them I saw that my QT/QTc was 372/462 on the printout. This of course scared me. I was told that these printouts are not always accurate and that I did not have long QT. They ordered a stress/echo to be on the safe side because of the stomach/chest pain and that was completely normal except for 5 isolated pvcs during the time they put me back on the table for the echo after I ran 16 minutes up to level 6.
So I agree with you that it isn't very reassuring when these machines can compute mistakes.
I have never fainted in my almost 50 years and I would imagine if I really had long QT that it would have shown up on this last stress/echo test.
I see a new cardiologist tomorrow. I will make sure and ask him about this again.
I have decided that I am not worrying about this anymore. I'm done trying to figure it all out. I have to trust these doctors at some point. I decided this about a month ago, and my heart has settled down and I actually have some days that I don't feel any skips at all.
So try not to stress too much until you get all your info back.
Wow, thats great that you are able to relax and move on! I thought I was doing great when I was having bigeminy then tri for quite the while the other day. I was so calm about it too. Then the pre-syncpe thing.... back to sqare one.
Well, your QT varies all the time. Take a look at the EKG on my profile, there you can see my QTc is 358 ms. That's a bit short, but in that case, my adrenaline levels were high despite my low heart rate. That decreases QT.
If you measure your QTc during times with high heart rate without physical activity or anxiety, your QTc may prolong.
What's important is that your REAL QT time, not corrected after the QTc formula, isn't above 500msec, because then (and only then) your risk of TdP increases. 95% of us have QT time at heart rate 60 of 360-440 msec (460 for women). That doesn't mean that 2,5% of us have LQTS (2,5% is above 440 and 2,5% is below 360).
The QTc formula is a mathematical formula that fails at higher heart rates. The phenomenon "LQTS" can the doctor see as specific changes in the T wave, it's usually not just prolonged, he can see changes consistent with potassium channel diseases, like a notched T wave.
A QTc (correced for heart rate) over 500ms is dangerous and can lead to Torsades. A QTc over 470ms for a woman and 460ms for a man is considered prolonged and needs to be checked out for causes, whether it is from medications, medical conditions or Long QT Syndrome, a prolonged QTc can result in Torsades.
The QTc is just a formula and the physicians still debate which of them should be used. At high heart rates, Bazett's formula will really often give high results results (close to 500 msec (at stress tests, etc.). When my mom had a stress test done, I asked her cardiologist about this specificly.
At heart rate 180 her QTc (Bazett) was close to 500 msec, the QT was 280 msec. If the Frederica formula is used (which it often is) the QTcF would be 404 msec.
I was wondering the same thing. My qt was 372 but my qtc was 462. Then they did a repeat ekg and my qt was 374 and qtc was 477. The ekg printout never stated long qt or possible long qt.
My heart rate was high as I was nervous (98). I have now asked 3 doctors about this and have been told the same things as you stated. They are not worried if it isn't over 500, plus they also told me that it would have been evident during my stress/echo last month or on any of my stress tests and ekgs over the last 20 years. They rely on those tests rather than just the ekg. I have to belive them. Jodie
We all have an unique profile on how the QT is narrowing with increasing heart rate. My QTc is a bit prolonged on high heart rates, possibly because my QRS is a bit wide (approx 105 msec) and this is included in the QT time.
At rest, rate 60, my QT is about 380 msec. At rate 80, it's about 340 (QTc 390), and at rate 100 it's 320 (QTc 413). Of course, this varies a lot with stress levels, etc.
It seems QT times are a bit dramatized at this community. LQTS is extremely uncommon, and it seems most people measuring prolonged QTc are "victims" of the famous Bazett over-correction with high heart rates.
ekgs are bewildering to me....when my QT/QTC was 398/473 my HR was 85 - the dr said something about prolonged QT and asked if anyone in my family had LQTS? I've also had QT/QTC intervals that were the exact same numbers which had doctors scratching their heads saying that's not possible.
too bad I don't have any ekg's where my HR has been high they might be interesting to see - I saw on my latest ICD interrogation I've had some NSVT runs where my HR was 350 - 425 which scared the heck out of me...luckily only 1-3 sec ranges.
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