User's Manual Part 2

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2.3.4. Filter Operation
Although it may appear that electrocardiogram (ECG) monitoring in the Magnetic Resonance
Imaging (MRI) area is similar to that performed in other areas of the clinical environment, the
conditions found inside the MRI area are unique and require additional precautions to be
followed in order to permit the safe monitoring of the patient during MRI procedures. Please
reference the ECG Monitoring section 6.1 for further ECG application details.
2.3.4.1. Monitor Mode
This filter mode provides ECG waveform filtering characteristics that meet the specification of
the Association for the Advancement of Medical Instrumentation (AAMI).
NOTE
• Note that this filter will not provide optimum performance during active MRI sequences.
2.3.4.2. MRI Mode
This filter mode provides special signal processing to reduce MRI gradient signals which
become superimposed upon the patient’s ECG. This MRI filter utilizes an adaptive slew rate
limiting scheme for reduction of gradient artifact generated by MR systems. The MRI Mode
filter also limits the ECG bandwidth to reduce the effects of magneto-hydrodynamic distortions
caused in the MR magnetic field and allow optimum HR counting. Resultant ECG waveforms
are not per AAMI standard nor AHA specification and may vary significantly from those
standards.