GE MAC 1200, Operator'S Manual

Page: 49 / 200

Revision C MAC 1200/1200 ST 4-9
2012250-021
Preparing for ECG Recording: Electrode Application
Artifact Due to Poor Electrode Application
The electrocardiograph is equipped with state-of-the-art electronic
utilities that ensure artifact-free recordings. Among these are the
automatic baseline adjustment and the anti-drift system (cubic spline)
(ADS).
At the beginning of the recording the automatic baseline adjustment
algorithm verifies the incoming signal and adjusts the baseline position
accordingly.
During the recording, the anti-drift system (cubic spline) continuously
checks the baseline position and returns it to the normal level, if
required (see Sample Recording figure).
For the Manual Mode, the anti-drift system (cubic spline) can be enabled
and disabled from the setup menu, in the Automatic and Arrhythmia
Modes, it is always enabled.
When electrodes are not properly applied, these measures may not fully
compensate for artifact. High polarization voltages induced by electrodes
applied without conductive gel may cause the amplifier to overrange, so
that a straight line will be recorded instead of the ECG (see figure). In
this situation the device will automatically block and return the baseline
to its normal position. A baseline is then recorded for approximately 1
second. It is possible to block the amplifiers manually by disconnecting
the R electrode.
Sample Recording
On the display this condition is indicated by **** instead of the electrode
label).
013A
approximately 1 second