EP 2 - PPT 1

What is the typical case starting workflow?

1) Patch + Validate

2) Check Metal Field

3) Physician Access

4) Set Metal Baseline

What impedance patch is the validation dependent on?

Left leg

When you press validate, what three things occur?

1) Starts an 18 hr timer (l.leg chip)

2) Starts the Ensite current

3) Baselines the impedance

Validating (or revalidating) will do what to models and maps?

deletes models and maps in both NavX and VoXel mode

What does checking metal field do?

compares current PRS-A measured position with known values collected during the lab characterization process

What are the recommendations when checking the metal field?

1) flat detector at highest position (AP-120)

2) table at abt 90 cm or 3 ft

3) PRS-A centered in magnetic detection box

What does setting metal baseline do?

sets a baseline for metal distortion for the remainder of the case

What are the recommendations for setting metal baseline?

table: physician desired height and position

flat detector: desired height in AP (without triggering metal distortion)

What is the definition of electroanatomical mapping?

a process that creates a 3-d map of the heart’s chambers showing how electrical signals propagate, combining:

• electrical data from the heart (timing and voltage of signals)

• anatomical location data (3D position inside the heart)

What are the 3 purposes of electroanatomical mapping?

1. diagnose arrhythmias

2. guide catheter ablation procedures

3. reduce reliance on fluoroscopy (x-ray imaging)

What purpose do catheters have in electroanatomical mapping?

measure electrical activity

What purpose does the mapping system have in electroanatomical mapping?

• tracks the position of the catheter in 3D space and builds a color-coded 3d model

• different colors represent voltage levels or activation timing

• helps identify abnormal tissue such as scar or arrhythmogenic circuits

What role do mappers play in Electroanatomical Mapping?

• operators who drive the system and interpret results

• collaborates with physician for treatment plan

What does a navigation mode include?

• coordinate system

  • tells us what’s up, down, L←→ R

• 3D space

What are the 3 mapping systems we compared (competitors)?

1. Abbott: Ensite

• Ensite X: NavX & VoXel

2. Medtronic: Affera

• Prism-1

3. Boston Scientific: Opal

4. Biosense Webster: Carto

What are Ensite’s Two Navigation Modes?

1. VoXel Mode - Magnetic-Based Mode

2. NavX Mode - Impedance-Based Mode

In NavX mode, how is the impedance field built?

Locating Electrode Patches

• 6 patient adhered electrodes

• generates low-intensity current via Ensite X amplifier

• placement of these electrodes result in our baseline impedance field

What are our 6 patient adhered electrode patches?

1. Neck

2. LL

3. Right Arm

4. Left Arm

5. Back

6. Front

In NavX mode, what are the 2 options as your positional reference?

1. System Reference (default)

2. Intracardiac Electrode Reference

T or F: System reference is the same as the system reference patch.

False; sys reference for positional reference is NOT the same as system reference patch

When is it best to use the system reference for positional reference?

• controlled and regular respiration pattern

• minimal patient movement is expected

• when general anesthesia is used for patient sedation

When is it best to use an intracardiac electrode for positional reference?

• potential for irregular respiration

• potential for patient movement

• when conscious sedation is used

What is the positional reference tool?

• detects and alerts the user of acute motion along the long axis of the catheter (‘push in/pull back’) and ignores lateral catheter motion (breaths/cardiac motion)

• uses a 3 minute moving average of the positional reference catheter location. when acute motion is detected, over 4 mm, the tool is triggered

When can the positional reference tool be enabled?

• when using an intracardiac electrode as the positional reference

How many electrodes have to be visible for the positional reference tool to be enabled?

4

Along what axis does the positional reference tool detect motion?

long axis (‘push in’ or ‘pull back’)

What are the benefits of NavX mode?

• following caths from the femoral and jugular vein

• mapping data collection in impedance mode

• supports NavX field scaling —> uses catheter spacing to create geomertry

• supports NavX SE field scaling —> enhances anatomic accuracy through linear scaling

Impedance Primary, Magnetic Secondary is for what mode?

NavX mode

In NavX mode, adding SE data (magnetic data) compensates for what?

non-linearity of impedance system

What are the drawbacks of NavX mode?

• unstable

• non-linear

Why does instability occur in NavX mode?

• impedance fields can change over time

• as properties of the impedance field change, the system’s understanding of catheter placement will shift in 3D space

Why does non-linearity occur?

Because impedance is resistance. An impedance field in 3D cardiac electroanatomic mapping consists of many different tissue types with different resistive properties.

What are the 3 factors that impact an impedance-based system?

• baseline vs arrhythmia state

• guidewires

• fluids

• respiration

Where can you access the system reference?

setup screen ONLY — under navigation

When using the catheter alignment tool, what steps do u do?

• shift, middle scroll button, & drag model to the appropriate site

• ensure u repeat process in multiple views

• Click the ‘Accept’ button to save any changes!

NavX Benefits vs Drawbacks

B:

• open platform w/ non-abbott products

• option for mapping when magnetics is not possible

• workflow w reduced fluoroscopy

D:

• non-linear

• impedance field is affected by changes in tissue properties

How is the magnetic field generated?

by the field frame

The magnetic field is used to localize what?

magnetic sensors

What is the origin of the VoXel coordinate system?

the calculated center of the three PRS-Ps

What are the PRS-Ps used to detect and compensate for?

patient movement

When is the magnetic field created?

when metal baseline is set

How far apart do the PRS-P’s have to be?

minimum 8 cm apart

What is a VoXel?

impedance fiducials that link the magnetic and impedance coordinate systems

What does collecting VoXels enable?

it enables impedance-based electrodes to be visualized and used by the system

How often are voXels collected?

continuously WHEN RespComp X is enabled

The VoXel cloud is visualized as what colored squares?

blue

What hot key toggles the display of Voxels squares?

CTRL + K

What mode is magnetic primary and impedance secondary?

VoXel mode

Only what type of catheters collect VoXels?

magnetic catheters

VoXel collection allows for the visualization of what type of tools?

non-SE tools (and distal electrodes)

What are the series of events that occur when there is an impedance change detection?

1. System continuously monitors VoXels (is continuously comparing to the impedance information)

2. Warning message appears if impedance change is detected

3. catheter goes to a partially-active collection status where all non-shaft electrodes turn yellow

4. Change

   1. If TRANSIENT, catheter returns to active collection state and continues data collection

   2. if PERMANENT, you must delete voXels and recollect + continue data collection

Does deleting VoXels delete your maps and models?

NO

What two things delete maps and models?

1) Resetting metal baseline

2) Revalidating

What factors impact a magnetic primary system?

• fluoroscopy machine

• anesthesia cart

• patient table (height)

What does metal distortion improve?

model accuracy by preventing data collection when the magnetic field is distorted

What is the default and max value for metal distortion in NavX mode?

default - I

Max - III

What is the default and max value for metal distortion in

default - I

Max - II

Step by Step when Metal distortion threshold is exceeded?

1) Distortion meter turns red

2) Data quality indicators all turn red

3) Catheter goes to non-active collection state with all yellow electrodes

To resolve:

4) remove extra metal that triggered threshold

5) return flat detector to previous location

6) accept a higher distortion threshold

VoXel mode benefits and drawbacks?

Benefits:

• independent of impedance conditions

• inherently linear

• stable over time

Drawbacks:

• affected by metal distortions

• sensor enabled tools required

• can only track catheters once in the field frame

Catheter visualization for inflexible vs flexible portion of the catheter?

• Inflexible proximal end of SE catheter is visualized based on magnetic data

• Flexible distal end of SE catheter location is visualized based on impedance & magnetic data

Effects of an impedance shift vs metal distortion issue?

Impedance shift —> can not collect VoXels

Metal Distortion Issue —> can not collect anything

When can standard catheters collect data and be visualized in NavX ?

always

When can sensor enabled tools collect data and be visualized in NavX mode?

always

When can standard catheters collect data and be visualized in VoXel mode?

• they can never collect data

• they can be visualized when in high confidence

When can the following catheters collect data and be visualized in VoXel mode: ?

• Advisor VL

• Advisor FL

• Legacy Grid

When in High confidence for both

When can the following catheters collect data and be visualized in VoXel mode: ?

• TactiCath

• TactiFlex

• FlexAbility

• Grid X

Always

What is the default positional reference in NavX mode?

System Reference

How is our 3D space generated in VoXel mode vs how is our coordinate system made?

3D space: field frame

Coordinate System: PRS-Ps

True or False - if the impedance change detection is triggered and the user selects ‘delete VoXels’, this will also delete all the models and maps

False

What is the basic map setup workflow?

1. Add Signals

2. Choose a reference

3. Measure the CL

4. Adjust Zero Offset

5. Adjust RAI Window

6. Freeze and Save First Point

7. Adjust Automap settings

What two detection algorithms are NOT available for reference detection?

1. Last Deflection

2. Near Field

What are the 7 Reference Detection Algorithms?

1. Max - peak pos.

2. Min - peak neg.

3. Abs Peak - largest peak from baseline, regardless of polarity

4. +dV/dt - sharpest positive slope

5. -dV/dt - sharpest negative slope

6. Abs dV/dt - sharpest slope, regardless of polarity

7. First Deflection - first deflection from baseline

True or False. All reference detection algorithms are available as roving detection algorithms.

True - however, not all roving are available as reference (last deflection, near field)

What does the Near Field roving detection algorithm detect?

the sharpest component of the signal, independent of amplitude

What type of signals are available for Near Field?

Omnipolar and bipolar signals

What is Default setting for detection sensitivity?

Auto

What would you change your detection sensitivity to ‘fixed’ for?

to more precisely target your point of interest; signals below the set sensitivity threshold will not be detected

The higher the sensitivity threshold, the _____ sensitive the system is to little bumps on the signal

less

What is the default reference detection?

ECG I, Max

What is the default roving detection?

• if OT Near Field installed: Near Field

• if OT Near Field not installed: Abs Peak

What roving detection algorithm should you think when you see “PEAK FREQUENCY”

Near Field

For reentrant rhythms, what should you set the RAI to cover?

Most of the Tachycardia cycle length

ex) for AFL with cycle length of 250 ms, set RAI from -123 ms to 123 ms

T or F: The first point serves as the reference for all subsequent points.

T

What is the hotkey to Freeze and Save a point?

F11

What hotkey cancels a point after you have hit freeze?

F12

Whenever you manually freeze or save a point, the system will keep a buffer with the current + the previous _ beats.

9

When automapping, the system only will keep a buffer with the current + the previous __ beats.

1

What is the score based on?

how much of the selected ECGS within the acquisition window matches underlying morphology to template beat