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Could someone tell me the current method for processing triplicate ECG
data? For example, should the mean or median of the QT be taken as
the QT value for that time?
Any assistance would be appreciated
Also, could you provide a good reference.
thanks
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The following message was posted to: PharmPK
Hello,
If QT values for triplicate ECG runs for a given time are close, then
arithmetic mean will be fine. However, if there is a great variation
in QT values, more ECG repeats should be done (e.g., 6 replicates),
and geometric mean or median of QT values should be used.
Hope this helps,
Khalid Alkharfy,
College of Pharmacy, KSU
Riyadh, Saudi Arabia
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The following message was posted to: PharmPK
Hello,
the issue is similarely complicated as in the case of PK parameters,
Cmax and
AUC.
As these PK parameters are log-normally distributed, the geometric
mean is
unbiased, and the arithmetic mean should not be used.
For ECG intervals, only few investigations have been made yet to
adress the
distribution of these parameters.
You might have a look at my presentation (16:00) on
http://epi.klinikum.uni-muenster.de/StatMethMed/2005/Heidelberg/Herbstworkshop2005.html
Slide 13 and 14 give an impression for a single data set (although
they are
not fully statistically correct).
The subsequent slides adress the issues on compatibility of the
derivations
and aggregation processes.
However, my impression is that the current industry standard in ECG data
analysis is taking the arithmetic mean value.
Moreover, heart rate correction of the QT interval is normally be done
before
aggregating the data per time point.
For more statistical discussions on cardiac safety, you might also find
information in the biopharmaceutical network:
http://www.biopharmnet.com/cardiac.html
There you can also find a new white paper in Section "Design and
analysis of
thorough QT studies", which for example adresses the number of ECGs
per time
point.
Mit freundlichen Gruessen / Kind regards,
Dr. Arne Ring
Boehringer Ingelheim Pharma GmbH & Co. KG
Phase I/IIa Statistics
Biberach
Germany
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