Ecgs Of Pacemaker Patients / Ecg Recording During Defibrillation - GE Marquette MAC 1200 Operator's Manual

8 ECGs of Pacemaker Patients / ECG Recording during Defibrillation

Recording ECGs of Pacemaker Patients
Due to the slow paper speed it is not possible to
display pacer pulses directly on the ECG recording.
At a paper speed of 50 mm/s and a pulse duration of
0.5 ms, the width of the recorded pacer pulse would
be only 0.025 mm.
For this reason the recorder reduces the pulse
amplitude and expands the pulse width, so that the
pacer pulse is easier to identify. The MAC 1200
records the pulse with the correct polarity, with a
width of 5 ms and with the same amplitude in all
leads (depending on the polarity of the pacer pulse in
leads I and II, the pacer pulse in lead III may be
suppressed). The amplitude of the reverse current
may differ from lead to lead. Figure 8-1 shows an
ECG recording with pacer pulses.
Figure 8-1. ECG recording with pacer pulses
If several adverse conditions exist at once, the
possibility that the pacer pulses are interpreted (and
counted) as QRS complexes should be considered.
At the same time, however, QRS complexes might be
suppressed in certain situations. Therefore,
pacemaker patients should always be watched
closely.
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ECGs of Pacemaker Patients / ECG Recording during Defibrillation
Warning
ECG Recording During Defibrillation
The patient signal input is defibrillation-proof so it
is not necessary to remove the ECG electrodes
before defibrillating the patient.
However, when using stainless steel or silver
electrodes, the defibrillator discharge current may
cause complete polarization at the electrode/skin
interface. This condition may prevent ECG signal
acquisition for several minutes. With silver/silver
chloride electrodes, this will not happen.
Set the MAC 1200 to 6 Lead Mode when you may
have to defibrillate the patient while recording the
ECG, and disable the anti-drift system as this would
cause a 2 second signal delay (section 9.3 "6 Lead
Mode").
If electrodes made of other materials are used,
disconnect the patient cable from the recorder while
the shock is applied.
− For reasons of patient safety, use only the
original Marquette patient cable. Before
connecting the cable to the device, check it for
signs of mechanical damage. Do not use a
damaged cable.
− Use silver/silver chloride electrodes for ECG
signal acquisition, if the patient may have to be
defibrillated.
− The patient signal input of the recorder is
protected against damage resulting from
defibrillation shocks. Nevertheless, extreme care
should be exercised when defibrillators are used
on a patient connected to other devices while a
shock is released.
− Observe the safety information of the
defibrillator.
− During defibrillation, do not touch the patient,
the electrodes or the leadwires.
MAC® 1200
Warning
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