A: This indicates disconnection in the pacing circuit external to the stimulator – it is not a EPS320 Cardiac Stimulator fault. Ninety-nine percent of time high impedance is caused by incorrect settings in the EP recorder, ie Stim channel not enabled or directed into channels with no catheter connected. Other times it is caused by disconnected or broken catheter.
90% of time high impedance is due to incorrect settings in the CardioLab – ie Stim channel not switched on, or directed into channels with no catheter connected. Rest of the time it is caused by disconnected catheter or broken catheter.
This is thus a very helpful feature in diagnosing cause of failure to capture pacing.
A: This (50Hz noise) may occur especially when EPS320 Cardiac Stimulator is installed remotely from patient (in the control room) with a long Stimulus Extension Cable in between or when other equipment is connected into the pacing circuit such as RF Ablators or 3D Mapping system.
We suggest you first connect pacing electrodes directly to the EP Recorder Catheter Input Module Stimulus Bypass outputs:
If noise intractable, EPS320 Cardiac Stimulator system may be split, locating the Stimulus Generator Unit under the bed, joined to the Bona PC via an RS232 cable.
A: Large stimulus spikes may occur with high stimulation currents, unipolar pacing or high impedance is pacing circuit. Check your settings and adjusting the clip on the EP Recorder channel may resolve the problem.
If you are getting high impedance warning and not capturing myocardium as well, then you have a break in one only of the +ve or -ve legs of the stimulation circuit. The remaining one connected circuit leg conveys a maximal voltage (almost 30V) to the myocardium trying to deliver the programmed current, but there is no return pathway for the current so none flows but a large spike is produced on the EP recorder. Correct this by rectifying broken circuit.
To locate the circuit break, connect pacing electrodes to the EP Recorder Catheter Input Module Stimulus Bypass outputs – if this rectifies problem then break is in connection between the stimulator and the EP Recorder Stim inputs; rarely the stimulator itself is faulty.
There have been unconfirmed reports of intermittent stimulus circuit interruption in EP Recorders, suspected to be related to concurrent use of 3D mapping devices.
A: This may occur with earlier EPS320 Cardiac Stimulator systems when used with GE CardioLab System. An upgrade to the EPS320 Stimulus Generator Unit resolves this issue. Contact Micropace.
A: This was due to a third party driver fault in software version 3.20.05, shipped from April 2005 to Dec 2005. Computer freeze occurs rarely and randomly on touching the touch screen anywhere. Stimulus Generator Unit enters Manual Backup mode, ready for emergency stimulation if required; product performance degradation causes no hazards. Rebooting computer recovers computer function.
More that 90% of affected software has been electively field-upgraded to 3.20.09 (SR3) between March 2005 and Nov 2005.
Workaround – use keyboard only and call Micropace for software upgrade which is performed on site via a USB Flash Drive.
A: Assuming noise is the commonest 50Hz – the circuit is picking up 50Hz – either being injected by some third party equipment or due to unbalancing of the stim outputs – unequal resistance in connections or selective grounding of the +ve or -ve wires in the Stim circuit.
You will need to determine more information and then contact your distributor or Micropace with it: