Philips Expression MR400 - Checking the ECG Signal Strength; Selecting the Scale

5‐16MonitoringECGExpressionMR400InstructionsforUse
Checking the ECG Signal Strength
EvaluatetheECGsignalproducedbythepatientbeforeentryintotheMRIscanner,the
optimumtimetocorrectanyproblem.
Aminimumsignalstrengthshouldbepresent,asweakersignalsmaybepronetogradient
interference:
• SelectScaletoadjustthedisplayedsizeofthewaveform(s),wherethescaleindicator

provides,a1millivolt(mV)referenceatanygivensetting;seeSelectingtheScale,below).
• SelectTraceALead(orTraceBLead )toadjusttheconfigurationoftheleadsusedforECG
signaldetection,wherethebestsignalstrengthisindicatedbythedisplayedpeak‐to‐peak
amplitudeof
theQRScomplex,whichshouldbeatleast1mV(thatis,thewaveform
shouldbeequaltothesizeofthescaleindicator).Insomecases, a1mVECGsignalcannot
beachievedduetopatientphysiology.Inthesecases,trytoachievethelargestamplitude
attainable.See
ChangingtheLeadView,onpage5‐17.
Selecting the Scale
TheScalesettingonlychangeshowtheECGtraceappearsonthescreen—increasingor
decreasingthewaveformandanyartifacts.ToincreasetheamplitudeoftheQRScomplex,refer
toChangingtheLeadViewonpage5‐17.
TochangetheSCALEsetting
Scale indicator
QRS complex
Step Action
1
EnsurethatthecorrectPatientTypehasbeenselected;seepage3‐
11fordetails.
2 SelecttheECGVSbox.
TheECGmenuappears.Currentsettingsaredisplayed.
3 SelectScale.
TheScalemenuappears;seepage5‐28.