User's Manual

Table Of Contents
7 ECG, Arrhythmia, ST and QT Monitoring
152
Recording The QT Waves
To start a recording,
•Select
Record QT.
QT Alarms
There are two QT alarms, QTc high limit alarm and QTc high alarm. The QTc high limit alarm is
generated when the QTc value exceeds the set limit for more than 5 minutes. The QTc alarm is
generated when the difference between the current value and the baseline value exceeds the set limit
for more than 5 minutes.
The
Cannot Analyze QT INOP and the -?- will be displayed when no QT measurement could be
calculated for 10 minutes. Up to this time the previous valid value will be displayed. The following
additional messages on the cause of the invalid measurements may also be displayed.
Switching Individual QTc Alarms On and Off
Each QTc alarm can be switched off individually.
To switch an alarm on or off, in the
Setup QT Analysis menu, select QTc Alarm or ΔQTc Alarm to
toggle between
On and Off.
Changing QTc Alarm Limits
Set the high alarm limits based on your assessment of the patient's clinical condition, unit protocols,
physician orders or medication specified limits.
1 In the Setup QT Analysis menu, select High Limit.
2 Select the appropriate setting.
Additional Message Cause of Invalid QT Measurement
QT Startup QT monitoring was just turned on or has been reset
Asystole or Leads Off 1 Not all specified leads needed to perform QT analysis are
available, or
2 Asystole condition is detected
Too few N labeled beats Not enough valid QRS complexes to generate a QT measurement
Invalid Rhythm for QTc Not enough valid RR intervals to generate QT-HR, the averaged HR
used for QTc calculation
High QT-HR QT-HR exceeds the specified upper limit of 150 bpm (for adults) or
180 bpm (for neonates and pediatrics)
Small R Wave R-wave of the signal is too small
Small T Wave T-wave of the signal is too small
End of T not Detected End of the T-Wave cannot be accurately detected
QT out of Range QT measurement is outside the specified range of valid QT values
(200-800 msec)
QTc out of Range QTc measurement is outside the specified range of valid QTc values
(200-800 msec)
QTc Erratic QTc measurements are not stable