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Fundamentals of EGM Interpretation and Fu da e ta s o EGM te p etat o a d Rhythm Analysis
Christine Chiu-Man, MSc Electrophysiology Pacemaker Technologist
The Hospital for Sick Children, Toronto, Canada
Intracardiac Electrogram 心内电图g
Electrodes record the local electrical activity:Electrodes record the local electrical activity:Sequence activation and timing
Normal tissue will show high frequency andamplitude signals (eg. 10 to 250 Hz)amplitude signals (eg. 10 to 250 Hz)
Diseased tissue may show low amplitudeDiseased tissue may show low amplitudefractionated signals
Catheters
Catheter curveElectrode spacing: 2mm, 5mm, 10mm, 2-10-2mm
How Are Electrograms Generated?
Band Pass Filter (Bipolar recordings)
High pass filter – removes low frequencyg p q y( Respiratory or motion oscillations) Eg. 30 Hz
Low pass filter – removes high frequency p g q y(Excessive large high frequency signals) Eg. 500Hz
Band pass – 30 to 500 Hz allows signals between 30 and 500 Hz to pass through
Stevenson JCE 2005;16:1017-1022.
p g
Intracardiac Electrogram 心内电图g
Morphology Duration
Amplitude Timing
Klitzner PACE 1990; 13:69-77
Intracardiac Electrogram 心内电图g
High pass Low pass Electrode spacingspac g
MorphologyMorphologyAmplitudeTiming
Duration
TimingKlitzner PACE 1990; 13:69-77
Intracardiac Electrogram 心内电图g
Klitzner PACE 1990; 13:69-77
Intracardiac Electrogram 심장내전기도g
Wavefront moving towards positive electrode(unipolar) -> positive deflection
W f i i i l dWavefront moving away positive electrode (unipolar) -> negative deflection
Bipolar: Electrical potential difference betweenBipolar: Electrical potential difference between two exploring electrodes at a given point in time.
Stevenson JCE 2005;16:1017-1022.
Intracardiac Electrogram 심장내전기도g
++
unipolarunipolar
bipolarbipolar
Mapping Considerations
DirectionalityUnipolar: Max negative slope (QS)Bipolar: Initial peak
DirectionalityYesN
Stevenson JCE 2005;16:1017-1022.
Bipolar: Initial peak No
Intracardiac Electrogram 심장내전기도g
+-
Catheter positioned near theright atrial appendage may
RAA
record a far field V wave in itsEGM in addition to the A wave
RAA
A V A VA V A V
His Bundle Electrogram
Catheter is straddled across the right atrialseptum near the tricuspid valveseptum near the tricuspid valve
Useful information on AV conduction (AV nodeUseful information on AV conduction (AV node,aberrant, pathway)
3 component electrogram :
LRA His V
A H V
1 , 2
Distal
The coronary sinusopens into the right
3 , 4
5 , 6
7 8p g
atrium. It may beapproached from the SVC
7 , 8
9 , 10
Proximal ppor from the IVC
CSCS
Depending on the take off from the left AV groove,h CS G d l A b h A d Vthe CS EGM may record only A wave or both A and V
waves.
A VProximal
A V
A VA V
A V
Distal
A V
Approach ECG Analysis 统系统的方式, 심전도분석접근법
QRS morphology
Rhythm regularityRhythm regularity
Rate
P-QRS relationshipQ p
Approach EGM Analysispp y심장내전기도분석접근법
Basic Rhythm
EGM MorphologyEGM MorphologyA, His, V
EGM Sequence of activation
Regularity rhythmAV relationship
Strategies for Interpretation
Relationship
Antegrade conductionHow are the impulses from the atriumpconducted to the ventricle?
Input(A)(A)
Output(V)
PACA V
A VH
A VH
VV
Strategies for Interpretation
Relationship
R d d iRetrograde conductionHow are the impulses from the ventricleconducted to the atrium?
Output(A)(A)
Input(V)
V A
A
VA H
A
V AVA V A
V AVA
PVCSinusV V
Stimulus V
A
A
AV
AV
V
Ventricular pacing
A A
Video 1: Baseline EGM and Ectopic Beats
Video 2: EGM Recognition During Pacing
Video 3: EGM Recognition During Mapping
Summary
Use surface ECG and catheter position identifiedUse surface ECG and catheter position identifiedby fluoroscopy to help determine the electrogramwaveformswaveforms.
Use baseline IEGM to help identify electrogramUse baseline IEGM to help identify electrogramwaveforms during arrhythmia (Look back approach).
Use the input/output approach to determineantegrade versus retrograde conductionantegrade versus retrograde conduction.
Th kThank you
多谢
감사합니다
ありがとうございますありがとうございます
