[Closed] Messing around with a 12 lead ECG at Uni

Give over.
QTc seems to be a bit open to interpretation, and is corrected for heart rate, so I'd not be concerned with a one off figure.

60 BPM here, I'll have a look for that. Any links for how to correct?

It wasn't one off though, we tried three of four repeats of reattaching the leads etc although I'm sure machines can vary in the readings they give.

I should probably go to the docs as my brothers had a few heart problems (although I'm not sure what they were).

http://en.m.wikipedia.org/wiki/QT_interval#section_1
Yes, its wiki, but it offers alternative calcs. Familial history might be important, but it seems unlikely.

Thanks Crikey.

Going by that I'm just above ULN. Pressures a bit high as well. 139/80 standing which wasn't what it used to be and 127/70 lying down.

QTc is corrected, that is what the 'c' is. 440ms is not too long, see below.

Google long QT syndrome and scare yourself, but wiki, as a start, is reassuring, especially in the absence of other symptoms/risk factors:

e a normal QT interval.[4] A commonly used criterion to diagnose LQTS is the LQTS "diagnostic score".[5] The score is calculated by assigning different points to various criteria (listed below). With four or more points, the probability is high for LQTS; with one point or less, the probability is low. A score of two or three points indicates intermediate probability.
QTc (Defined as QT interval / square root of RR interval)
[b]>= 480 msec - 3 points
460-470 msec - 2 points
450 msec and male gender - 1 point[/b]
Torsades de pointes ventricular tachycardia - 2 points
T wave alternans - 1 point
Notched T wave in at least 3 leads - 1 point
Low heart rate for age (children) - 0.5 points
Syncope (one cannot receive points both for syncope and torsades de pointes)
With stress - 2 points
Without stress - 1 point
Congenital deafness - 0.5 points
Family history (the same family member cannot be counted for LQTS and sudden death)
Other family members with definite LQTS - 1 point
Sudden death in immediate family members (before age 30) - 0.5 points

I'm used to medical textbooks being scary as **** so I don't get worried but thanks. Yeah it doesn't seem too bad, the raised blood pressure and mild orthostatic hypertension has me a little befuddled though. I rarely go to the docs so I suppose it's probably just a good idea to go and have a yearly mot.

It just threw up a red flag for me because my brother had tonnes of appointments with a cardio, I'll ask him what it was about.

Doing this is good practice I guess if I ever want to do clinical sciences in a hopsital or go to graduate medical school.

..as a not very scientific approach, I would tend to view 'corrected' measurements, especially those done in relative isolation with a bit of caution.

Reliance on algorhythms (I've tried spelling that about 6 times..) to derive figures which are then checked against 'norms' is a bit of a black art. I'm thinking about FTc; Flow time corrected from oesophageal doppler machines; can be useful, can show trends, but not a figure to be used alone.

I'm off to work now!

if you are concerned go see a doc for sure, patients don't follow textbooks and you have to remember reference ranges are for the 95% of the population and the like, i would have thought if your bro's condition was a risk factor they should have offered you some tests back then?

I wouldn't use wiki, google gp notebook or patient.co.uk they normally have reliable information and advice how to proceed. Was the session surpervised? no one to get some advice from?

Do let us know tho....

to quote - http://emedicine.medscape.com/article/157826-overview (generally reliable)
The QT interval on the ECG, measured from the beginning of the QRS complex to the end of the T wave, represents the duration of activation and recovery of the ventricular myocardium. A QT interval corrected for heart rate (QTc) [b]that is longer than 0.44 seconds is generally considered to be abnormal[/b],

and if you go to
http://emedicine.medscape.com/article/157826-workup
there is a point scoring system and a QTc of 440 doesn't give you a score, it only starts being important when more than 450...

Agree with all of the above. 440 is normal.

The machine also gets it wrong pretty often in my experience. You can check it manually by dividing the QT interval by the square root of the R-R interval. The QT interval is the distance in milliseconds from the beginning of the Q wave to the end of the T wave. Try it on a few different complexes and you'll get an average.

HTH
Hannah
Cardiology Reg

QTc(B)azett or QTc(F)redericia correction?
(individual baseline is the one I like best in studies but you need a lot more data for this). The correction can make a difference, but 440 would be considered normal.

Are you taking any medications?

EDIT forgot to ask are you male or female. We look at a lot of QTc data for TdP. A nice presentation on the matter [url= http://www.fda.gov/ohrms/dockets/ac/01/slides/3746s_01_Ruskin/sld001.htm ]here[/url]