User's Manual

QT Interval Monitoring
6-44 ECG and Arrhythmia Monitoring
Adjusting QT Settings
For patients being monitored by the MX40, you can turn QT Monitoring
on/off and adjust QT settings at the IntelliVue Information Center.
 To turn QT Monitoring on/off at the IntelliVue
Information Center Release N:
1 From the Patient Window, click the All Controls button.
2 From the All Controls Window, click the QT Setup button.
3 From QT Setup, click the QT Analysis On checkbox.
QT analysis is on when a checkmark displays in the check box. When the
QT measurement is on, a QT status message is displayed in the QT Setup
window, along with the current values for QT, QTc, dQTc and QT-HR. The
lead labels indicating the leads used to calculate the baseline and current
values also appear.
 To turn QT Monitoring on/off at the IntelliVue
Information Center iX:
1 Select the Measurements button from the Main Setup Window.
2 From the Measurements Window, select QT.
3 Click the I/O QT Analysis button to toggle on or off as appropriate.
The table below provides descriptions for each of the QT measurement
descriptions.
Measurement
Definition
QT
QT interval in milliseconds. The QT interval is the time between the
beginning of the Q-wave and the end of the T-wave.
QTc
QTc represents the heart rate corrected QT interval. By default, the
Information Center uses the Bazett correction formula to correct
the QT interval for heart rate. Your system, however, may be set
up to use the Fridericia correction formula.
dQTc
The difference between the current QTc value and the QTc
baseline value.
QT-HR
The heart rate used to calculate QTc
Note—Turning QT analysis off does not clear the baseline value. This
allows you to turn QT analysis off during prolonged arrhythmias, such as
bigeminy, without losing the baseline.