See also: Hampton1 animal documentation

Rapid screening of Electrocardiograms (ECGs)
For additional details and results, see Chu et al. 2001 and www.MouseSpecifics.com Prior to these tests, mice were evaluated in a Comprehensive Lab Animal Monitoring System (CLAMS) at the Jackson Laboratory by Dr. Kevin Seburn (data available). Mice were shipped to Boston immediately after CLAMS. After a 3-day acclimation period, mice were subjected to ECG.
^{TM}
incorporates Fourier analyses and linear time-invariant digital filtering of
frequencies below 2 Hz and above 100 Hz to minimize environmental signal
disturbances. The software uses a peak detection algorithm to find the peak of
the R-waves and to calculate heart rate (see Figure 1).
Heart rate variability was calculated
as the mean of the differences between sequential heart rates for the complete
set of ECG signals. Subsequently, determination of 1^{st} and
2^{nd} derivatives and algebraic "if-thens" search the ECG
signals for probable P-wave peaks and onset and termination of QRS complexes.
Because the T-wave is not separate from the QRS in rodent
ECGs [Bestetti,Richards], there have been discrepancies in the definition of the QT interval and
reported values [Mitchell]. In accord with Mitchell et al., we routinely included
the inverted and/or biphasic portions of the T-wave in our calculations of the
QT interval. We defined the end of the T-wave of each signal as the point
where the signal returned to the isoelectric line [Wang,Kirchhoff] [the mean voltage
between the preceding P-wave and QRS interval]. The QT intervals were rate
corrected (QTc) by application of the equation recommended by Mitchell et al.
[Mitchell] for use in mice. The software plots its interpretation of P, Q, R, S, and
T for each beat so that spurious data resulting from unfiltered noise or motion
artifacts may be rejected. e-MOUSE
then calculates the mean of the ECG time intervals for each set of
waveforms.
## Figure 1 |