ECG Monitoring
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8.7.9 Locate ST Point, J Point and ISO Point
ST measurement, or ST segment deviation, refers to the vertical distance between the isoelectric line (ISO) and the
ST point. The isoelectric line is located between the end point of the P wave and the beginning point of the QRS
complex, providing a measurement baseline. ST point is in the middle of the ST segment, J point is the end point of
the QRS complex. Since the distance between the J point and ST point is fixed, you can accurately locate the position
of the ST point by the J point.
(1) ISO Point (2) J Point (3) ST Point (4) ST Value
If the HR or ECG wave of the patient changes obviously, the position of ISO and ST points should be
adjusted. During ST segment analysis, abnormal QRS complex is ignored.
Please ensure that the position of the ST measuring point is suitable for the patient being monitored.
8.7.9.1 Set ST Point, J Point and ISO Point
1) Select the ECG parameter, waveform, ST parameter or ST segment waveform area to enter [ECG] menu.
2) Select [ST] tab → [Adjust ST Point] tab.
3) Select [ST Point] to set the position of ST point.
4) [Auto Adjust] means the adjustment mode of the ISO point and the J point. The Auto Adjust switch is [ON] by
default, and the monitor automatically adjusts the position of the ISO point and J point based on the current
model. If the [Auto Adjust] is set to [OFF], you can click on the arrows to the right of [ISO] and [J] to manually
adjust the position of the ISO point and the J point.
The ISO point cursor indicates the position of the isoelectric point relative to peak R wave. The ISO point
is located at the middle of the flat section of the baseline (between P wave and Q wave).
The J point cursor indicates the position of the J point relative to peak R wave. It helps to locate the ST
point correctly. The J point is located at the end of QRS complex and the beginning of the ST segment.
The distance between the ST point and the J point is fixed, so move the J point to make the ST point in
the middle of the the ST segment. The ST point may be located at J+60/80, J+40, J+60 or J+80. If [J+60/80]
is selected the system will automatically adjust the position of the ST point according to the patient's
heart rate: when the patient's heart rate is greater than 120bpm the system will select J+60 to locate the
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