1. How to Select a Reference Channel, Set a WOI and Annotate EGMs of the Mapping Catheter with

2. Selecting a Reference Channel

3. What is the Reference Channel
The Reference channel (REF) is a signal which is the fiduciary point in which all EA points are measured against
Window of Interest (WOI) will be built around the REF channel
Used as the Zero point for LAT maps
Used to visually Gate Map Catheter location
Generally speaking the REF channel should reflect the chamber being mapped
Atrium should reference an Atrial signal
Ventricle should reference a Ventricular signal

4. What is the Reference Channel
In the Map Setup, select a REF channel from the drop down
Select a REF channel that is appropriate to the chamber you are mapping
Atrium = CS Atrial electrogram
Ventricle = BS QRS

5. What is the Reference Channel
Atrial Reference (CS A)
Maps of Atria
Atrial Tach, Atrial Flutter, PV Tach, Sinus Tach, Normal Sinus Rhythm
Ventricular Reference (QRS)
Maps of Ventricles
LAT, Bipolar Maps
Anatomical Maps
Afib, AVNRT, Isthmus lines
AVRT may use the QRS as a REF channel, because the ventricle is part of the circuit and there is a fixed AV or VA ratio

6. Atrial Reference Atrial Reference Options Coronary Sinus Catheter
Best choice as CS is stable, unlikely to be dislodged
Choose a Reference that is physically close to the chamber being mapped
CS 7-8 or 9-10 for Right Atrium
CS 1-2 for Left Atrium
Choose an REF channel in which the A waves are larger that the V waves
High RA Quad Catheter
Use only if CS not accessible
Stability is an issue – position in RAA
Snapshot location
Lasso® Catheter pair occasionally used, positioned in LAA V A

7. Ventricular Reference
A body surface QRS will provide the most stable reference for any Ventricular Rhythm
You may consider BS QRS for:
Anatomical Maps in which EA information is not acquired
Anatomical Maps of Afib
AV Nodal Reentry Tachycardia (AVNRT)
Anatomical ablations such as Caval Tricuspid Isthmus lines
Atrial Ventricular Reentry Tachycardia(AVRT), as there is constant 1:1 AV or VA ratio

8. REF Channel Criterion
Once you have selected a REF channel, you will have to determine where you would like the system to annotate the waveform
Choices are:
Maximum Value
Minimum Value
Up Slope
Down Slope
MAXIMUM VALUE

9. Maximum Value Annotation on the highest amplitude of the ECG
Animate: 1 of 4. See original for timing of the waveform.

10. Minimum Value Annotation on the lowest amplitude of the ECG
Animate: 2 of 4. See original for timing of the waveform.

11. Up Slope Annotation on the most positive slope of the ECG
Slope is an option only if choosing pacing artifact as the reference
Animate: 3 of 4. See original for timing of the waveform.

12. Down Slope Annotation on the most negative slope of the ECG
Slope is an option only if choosing pacing artifact as the reference
Animate: 4 of 4. See original for timing of the waveform.

13. REF Annotation Criterion
When selecting an annotation criterion, it is important to visualize the EGM of the REF channel on the Carto® 3 System to determine the annotation criterion
In this tracing, there are two positive deflections of equal amplitude and one large negative deflection on the REF 9-10
Maximum Value poor choice
Maximum Value good choice

14. REF Annotation Criterion
If we were to select REF 9-10, maximum value, the system may have difficulty in determining which positive deflection to annotate from beat to beat. Minimum value would be a better choice for CS 9-10
But in this example, we decide to choose another electrogram, REF 3-4, Maximum value as the REF channel, as there is only 1 positive component to the electrogram
Maximum Value poor choice
Maximum Value good choice

15. Verify REF in Monitor Window
After selecting a Reference channel, visually verify in the monitor window that your reference annotation is consistent and reproducible
Notice that the REF annotation is marking each and every Atrial signal at it’s maximum peak, but ignoring all Ventricular signals. This is a reliable choice.

16. Verify REF in Monitor Window
This is an example of a poor choice for a REF channel selection
Notice that the REF annotation is identifying both atrial and ventricular signals on the CS catheter
Another pair of electrodes should be selected

17. Beware of Wandering Reference
Pick your reference carefully
Surface ECG Reference Designation

18. Pacing Artifact as Reference
Pacing artifact can be used as a reference
It is reliable, reproducible, stable
Identify a QRS or EGM that has a prominent pacing spike (Ld II in the example)
Select Up/Down Slope for REF Criterion - or Minimum/Maximum Value
Set WOI From: +10 ms to exclude pace spike .
Pacing Spike (Select a REF channel with a prominent spike)
+10

19. Recap Pick your reference correctly
Correct reference – easy for system to recognize
Reliable and Reproducible
Clean, sharp signal that will remain stable
No far-field signals from other chambers
Incorrect reference – can distort map
V signals annotated instead of A signals in CS
Changing deflections of BS QRS in VT
Changing deflections of CS A with respiration

20. Window Of Interest

21. What is Window of Interest?
Time window is defined relative to the reference annotation - From and To Margins
User determines values of WOI based on the chamber, mechanism and CL
Time frame within the cardiac cycle during which the system is looking for the mapping annotation criterion
From To
Time 0
Reference ECG
LAT= +71
Mapping Channel
-100
+250
From To

22. What is Window of Interest?
Annotation Viewer Window
“From” Line
i.e., -250 (relative to REF channel)
“To” Line
i.e., +100 (relative to REF channel)
Reference Annotation
Zero Point
Mapping Annotation
Local Activation Time (LAT) is relative time to reference zero
Left of REF = negative number
Right of REF = positive number

23. What is Window of Interest?
Annotation Viewer Window
“From” Line
i.e., -250 (relative to REF channel)
“To” Line
i.e., +100 (relative to REF channel)
Reference Annotation
Zero Point
Mapping Annotation
Local Activation Time (LAT) is relative time to reference zero
Left of REF = negative number
Right of REF = positive number

24. What is Window of Interest?
Annotation Viewer Window
“From” Line
i.e., -250 (relative to REF channel)
“To” Line
i.e., +100 (relative to REF channel)
Reference Annotation
Zero Point
Mapping Annotation
Local Activation Time (LAT) is relative time to reference zero
Left of REF = negative number
Right of REF = positive number

25. What is Window of Interest?
Annotation Viewer Window
“From” Line
i.e., -250 (relative to REF channel)
“To” Line
i.e., +100 (relative to REF channel)
Reference Annotation
Zero Point
Mapping Annotation
Local Activation Time (LAT) is relative time to reference zero
Left of REF = negative number
Right of REF = positive number
--78
-250
102

26. What is Window of Interest?
Annotation Viewer Window
“From” Line
i.e., -250 (relative to REF channel)
“To” Line
i.e., +100 (relative to REF channel)
Reference Annotation
Zero Point
Mapping Annotation
Local Activation Time (LAT) is relative time to reference zero
Left of REF = negative number
Right of REF = positive number
--78
-250
102

27. What is Window of Interest?
Annotation Viewer Window
“From” Line
i.e., -250 (relative to REF channel)
“To” Line
i.e., +100 (relative to REF channel)
Reference Annotation
Zero Point
Mapping Annotation
Local Activation Time (LAT) is relative time to reference zero
Left of REF = negative number
Right of REF = positive number
--78
-250
102

28. How to Set the WOI
Determine mechanism of tachycardia – Focal or Reentry?
Rules of Thumb:
If Reentry, set WOI to % of TCL – 3 formulas to choose from:
Split WOI 50/50: i.e., TCL = 300 = 300/2 From: -150 To: +150
2/3-1/3 method: i.e., TCL = 300, 300/3=100 From: -200 To:+100
DePonti Method: % of TCL, WOI adjusted so that P wave falls in middle of window
Atrial Focus
From: Pre P wave onset by msec To: onset of QRS
Ventricular Focus
From: Pre QRS onset by ms To: beyond end of QRS

29. Recap Set the Window of Interest (WOI) correctly:
Avoid erroneous data from signals outside window
For focal arrhythmias, set window to ms pre-P (AT) or QRS (VT) onset
Helps exclude artifact, signals from wrong chamber
For macroreentry, set window width to 95% of TCL
All sites will appear only once within window of interest
<90% of TCL: some sites will fall outside window
>100% of TCL: some sites will be in window twice

30. Annotating the Mapping Signal

31. Selecting a Map Channel
In the Map Setup, select a Mapping Channel from the drop down menu. Options are:
MAP 1-2 (Default) Recommended
MAP 3-4 M1 M2
Options to Select a Mapping Criterion
Maximum Value
Minimum Value
Up Slope
Down Slope
As Map signals are collected from a roving catheter, it is important to annotate every time, thus default map criterion (maximum value) is acceptable
MAXIMUM

32. How to Annotate LAT Maps
What chamber are we mapping?
If it lines up with QRS, it is probably a V
Beat Buffer to previous beat if unclear

33. How to Annotate LAT Maps
What chamber are we mapping?
If it lines up with QRS, it is probably a V
Beat Buffer to previous beat if unclear
What signal should you annotate?

34. How to Annotate LAT Maps
What chamber are we mapping?
If it lines up with QRS, it is probably a V
Beat Buffer to previous beat if unclear
What signal should you annotate?
What channel are we referencing?

35. How to Annotate LAT Maps
What chamber are we mapping?
If it lines up with QRS, it is probably a V
Beat Buffer to previous beat if unclear
What signal should you annotate?
What channel are we referencing? CS

36. How to Annotate LAT Maps
What chamber are we mapping? Atrium
If it lines up with QRS, it is probably a V
Beat Buffer to previous beat if unclear
What signal should you annotate?
What channel are we referencing?
What signal is this? CS

37. How to Annotate LAT Maps
What chamber are we mapping? Atrium
If it lines up with QRS, it is probably a V
Beat Buffer to previous beat if unclear
What signal should you annotate?
What channel are we referencing?
What signal is this? CS

38. LAT Map Annotation
The system will automatically assign an annotation based upon the Map Annotation Criterion
Many physician will ask you to annotate the signal to the earliest deflection from baseline on the M1-M2 signal
Earliest Annotation

39. LAT Map Annotation
The system will automatically assign an annotation based upon the Map Annotation Criterion
Many physician will ask you to annotate the signal to the earliest deflection from baseline on the M1-M2 signal
Earliest Annotation

40. LAT Map Annotation
The system will automatically assign an annotation based upon the Map Annotation Criterion
Many physician will ask you to annotate the signal to the earliest deflection from baseline on the M1-M2 signal
Others will prefer annotation to earliest sharp deflection on M1-M2 that correlates with the sharpest down slope of the unipolar (M1)
Earliest Annotation
Earliest Sharp Annotation

41. How to Annotate LAT Maps
Annotation is clear when you have sharp, distinctive electrograms

42. How to Annotate LAT Maps
Annotation is clear when you have sharp, distinctive electrograms

43. How to Annotate LAT Maps
Annotation is clear when you have sharp, distinctive electrograms
Annotation is not so clear if there is slowed conduction in scar, double potentials or Early meets Late in the WOI. Be consistent

44. How to Annotate LAT Maps
Annotation is clear when you have sharp, distinctive electrograms
Annotation is not so clear if there is slowed conduction in scar, double potentials or Early meets Late in the WOI. Be consistent

45. How to Annotate LAT Maps
Annotation is clear when you have sharp, distinctive electrograms
Annotation is not so clear if there is slowed conduction in scar, double potentials or Early meets Late in the WOI. Be consistent

46. How to Annotate LAT Maps
Annotation is clear when you have sharp, distinctive electrograms
Annotation is not so clear if there is slowed conduction in scar, double potentials or Early meets Late in the WOI. Be consistent DP

47. How to Annotate LAT Maps
Annotation is clear when you have sharp, distinctive electrograms
Annotation is not so clear if there is slowed conduction in scar, double potentials or Early meets Late in the WOI. Be consistent DP

48. How to Annotate Signals Early Meets Late Signals
Set WOI to % of TCL to avoid having 2 beats in window
Take another point or use beat buffer if unsure
Copy of RA FINAL.CSZ-3rd map

49. How to Annotate Signals Early Meets Late Signals
Set WOI to % of TCL to avoid having 2 beats in window
Take another point or use beat buffer if unsure
Be consistent as to where you mark
Copy of RA FINAL.CSZ-3rd map
Earliest deflection is inside window
Earliest deflection is outside window

50. Annotate by Location Earlys should be marked late
Set WOI to 95%-100% of TCL
Images courtesy of Dr. Abrar Shah, University of Rochester Medical Center

51. Early Meets Late Annotation

52. How to Annotate by Location
Late based upon distance from circuit
Late based on neighboring points
Counterclockwise Type I Flutter

53. Annotation
Not clear if EGC on M1-M2 is A or V or both – use the Beat Buffer to scroll back to another beat for clarification

54. Annotation
Not clear if EGC on M1-M2 is A or V or both – use the Beat Buffer to scroll back to another beat for clarification

55. Annotation
Not clear if EGC on M1-M2 is A or V or both – use the Beat Buffer to scroll back to another beat for clarification
Beat buffered
Annotate a signal

56. Annotation
Not clear if EGC on M1-M2 is A or V or both – use the Beat Buffer to scroll back to another beat for clarification
V signal aligns with QRS
Beat buffered
Annotate a signal

57. Annotation
Not clear if EGC on M1-M2 is A or V or both – use the Beat Buffer to scroll back to another beat for clarification
V signal aligns with QRS
Beat buffered
Annotate a signal

58. Annotation
Not clear if EGC on M1-M2 is A or V or both – use the Beat Buffer to scroll back to another beat for clarification
V signal aligns with QRS
Beat buffered
Annotate a signal

59. LAT Annotation in Slow/Scar Border
System automatic annotation
User defined annotation

60. WOI and Annotation during Bipolar Map
Bi (mv) is the average peak to peak voltage measure on M1-M2 in the WOI
Avoid pacing artifact in WOI in voltage mapping as this artificially elevates voltages in map
Normal voltage
3.86mv

61. WOI and Annotation during Bipolar Map
Bi (mv) is the average peak to peak voltage measure on M1-M2 in the WOI
Avoid pacing artifact in WOI in voltage mapping as this artificially elevates voltages in map
No need to annotate EGM in Bipolar maps
Normal voltage
3.86mv

62. Map Annotation in Bipolar Map
Voltage is measured as the average peak to peak voltage on the M1-M2 signal that falls within the WOI
With low voltages, it is important to confirm catheter contact
Annotation not necessary in Voltage maps

63. Map Annotation in Bipolar Map
Voltage is measured as the average peak to peak voltage on the M1-M2 signal that falls within the WOI
With low voltages, it is important to confirm catheter contact
Annotation not necessary in Voltage maps

64. Test Your Knowledge Which Chamber was intended to be mapped?
Ref is CS, however only V electrogram is visible – select another channel that displays prominent A signal
CS 1-2
M1-M2
Default WOI

65. Test Your Knowledge Which Chamber was intended to be mapped?
Ref is CS, however only V electrogram is visible – select another channel that displays prominent A signal
Which signal should be annotated on M1-M2 ?
Atrial
CS 1-2
M1-M2
Default WOI

66. Test Your Knowledge Which Chamber was intended to be mapped?
Ref is CS, however only V electrogram is visible – select another channel that displays prominent A signal
Which signal should be annotated on M1-M2 ?
Atrial
Was WOI set correctly?
No, this is the default WOI and includes both A and V
CS 1-2
M1-M2
Default WOI

67. Annotating Accessory Pathways
Manifest (WPW) can map in:
Sinus Rhythm
A pacing
V pacing
Tachycardia (Orthodromic or Antidromic)
Concealed can map in:
Tachycardia (Orthodromic)

68. Accessory Pathways with V Pacing
REF – CS 5-6 Max Value
WOI adjusted to exclude pacing artifact from WOI
Mapping along annulus should result in a VA signal
Move annotation to earliest A
REF CS 5-6, Maximum Value
Early site -33 ms
V A
V & A fused
Annotate to earliest A
Annotate to earliest A

69. Accessory Pathways with Atrial Pacing
Can only use with a Manifest pathway
Atrial pacing slows AV node conduction with increasing paced rates, causing greater preexcitation though AP (Delta wave becomes more pronounced)
Annotate to earliest V on M1-M2, correlate with M1 if unclear
A pacing spike
Delta wave M1
Antegrade A
Antegrade V

70. Recap Annotate Map activation times correctly
The system will always pick an activation time
All activation points acquired must have operator oversight
Problematic situations:
Complex electrograms (scar-based AT or VT)
Sites on annulus with both A and V signals
It only takes 1 or 2 points with incorrect activation times to mangle a map

71. How to Build A Map
Verify CL is consistent with TCL A V A

72. How to Build A Map
Verify CL is consistent with TCL A V A

73. How to Build A Map Verify CL is consistent with TCL
Verify REF channel is annotating correctly A V A

74. How to Build A Map Verify CL is consistent with TCL
Verify REF channel is annotating correctly
Verify WOI is set correctly A V A

75. How to Build A Map Verify CL is consistent with TCL
Verify REF channel is annotating correctly
Verify WOI is set correctly
Identify the waveforms A V A
QRS

76. How to Build A Map Verify CL is consistent with TCL
Verify REF channel is annotating correctly
Verify WOI is set correctly
Identify the waveforms
Verify or move annotation to correct location A V A
QRS

77. How to Build A Map Verify CL is consistent with TCL
Verify REF channel is annotating correctly
Verify WOI is set correctly
Identify the waveforms
Verify or move annotation to correct location
Visualize color progression on map – It should make sense A V A
QRS

78. How to Build A Map Verify CL is consistent with TCL
Verify REF channel is annotating correctly
Verify WOI is set correctly
Identify the waveforms
Verify or move annotation to correct location
Visualize color progression on map – It should make sense
Do these steps for every point acquired A V A
QRS

79. Authored by: LTomecha@its.jnj.com
Happy Mapping!
Authored by: