Week 2 Biophysics & Carto 3 System

Components of RF circuit

RF Gen → RF cable & cath → patient → grounding pad/indifferent electrode

Importance of grounding pad

Prevents dangerous heat buildup in patient body

• Collects energy and funnels back to generator

• Distributes electrical energy across large surface area

• Improper placement can increase impedance (small area concentration) & disrupt flow of energy (potentially cause burns)

Patient size and location very important

• larger patient = higher impedance

• farther from heart = higher impedance (want shorter distance)

Resistive Heating

Heat directly adjacent to electrode

• hottest portion

• resistance in myocardium causes ions to become agitated and cause heat in the tissue

• 3 mm

Conductive Heating

Expanded area from resistive heating area

Majority of lesion size

Allows damage to penetrate deeper into heart

• 7 mm

• need proper ablation contact & time

3 factors affecting lesion size

Time (s): duration correlates to lesion size

Contact F (g): Pressure caused by catheter tip

• Can be monitored by US to assess contact

• TPI = tissue proximity index (sparkle = good)

• varipulse = bubbles show = good

Power (W): GREATEST role

• Amount of RF energy delivered to the tissue

• power delivered does not equal energy received

Impedance

Resistance to electrical flow between catheter tip and grounding pad

• Should see gradual drop during ablation (less impedance = dead tissue)

Important temperatures RF ablation

50-55 C = Cell death

75 C = Char & Coagulation

• Overheating & decrease efficiency of energy delivery

• Causes sharp rise in impedance

100 C = steam pop

• overheating & over ablation

Apoptosis with PFA

Irreversible cell death from applied electrical fields that cause pores in the cell membrane causing an imbalance and eventually death

• tissue specific & maintains tissue elasticity

• Distance from other structures decreases risk of harm to other structures

• stunning can occur (improper time for lesion formation)

Variable in PFA waveform

Pulse strength & duration

Bipolar vs unipolar

Monophasic vs biphasic

# of pulses

frequency

Importance of good contact PFA

Need multiple applications ( 4 per PV for varipulse)

Good contact needed for increased lesion depth

Uniform cell death in blast zone

Power modes for the NGen

Power controlled mode: RF energy @ a fixed target power

Temp controlled mode: Temp & power change

• QDOT

• Changes power & fluid output to prevent overheating

Connections to the NGen

NGen Pump

Console & power supply

Monitor

Workstation

Carto3 System Tower

PIU core of Carto

• Receives real time location & ECG calculations

• Interface with cath & other equipment

• Info goes into PIU and spits out back to WS

Workstation

Gathers data from PIU

Creates 3D electroanatomical map of heart

DVI cables

Connects secondary monitor to carto WS

• Allows primary monitor image to display on secondary monitor in real time

Ethernet

Connects NGen generator to Carto WS

Connects NGen monitors & console

• Navigant = WS

• US = US

IC Out (back of PIU)

Transmits intracardiac signals from PIU to recording system

Fiber optics

Connects WS to PIU (transfers data)

Serial communication cable

Connects console to recording system

Patch unit

Connects patches & transfers data from patient to PIU

Patches

Measure high f & low power current emitted from cath electrode connected to the system

• Determines initial body coordinate system (BCS) based on 3 back patches & relative to each other & magnet

Location pad/magnet

Contains magnetic coils to generate magnetic field to see cath location

ECG In

Transfers ECG data from patient to PIU

ECG Out

Transfers body surface ECG signals from PIU to recording system

NGen console to PIU cable

Connects PIU to NGen console (data transfer)

Pump

Sets irrigation flow rate for navigational caths

Console & power supply

RF generator solution for current & future cathetera

Automatically recognizes NAV caths & loads default ablation & irrigation settings

Monitor

Controls pump & remote monitor

Controls system

Electroanatomical Mapping

Recording and cataloging endocardial electrical data & creating detailed rendering of heart anatomy

Impedance based tech

Catheter is placed and then impedance can be measured & cath can be visualized

• Impedance measured between 2 patches

Pros:

• Any cath can be visualized

Cons:

• Non-linear field

• Biological processes can disturb impedance

• Impedance can change w/ each cath inserted

Magnetic Technology

Uses magnent, patches, and sensor based cath

Sensor measures strength of magnetic field based on distance from each coil on location pad

• tip location = x,y,z axis

• orientation = roll, pitch, yaw

Pros: VERY accurate

Cons: Only supports NAV based caths (need to have sensors)

Current based tech

System generates small current & sends to caths → each electrode emits unique f which is collected by patches

Pros:

Does not need to be magnetic to be visualized

Carto Advanced Cath Location (ACL)

Combo of magnetic & current based technology

• Location & current ratio stored everywhere where the cath visits → system links ratio w/ magnetic location → visual location of cath

• Sensor based cath can create matrix (made of current ratios taken from electrodes) & match to magnetic location → can see non-NAV/non-sensor based cath

Pros:

Visualization of any cath with electrodes

Creates linear field

Not impacted by biology changes

Very accurate (1 mm)

6 degrees of freedom (DOF) = more precise

MAP Port

NAV therapeutics ONLY

Cables with red end

Ex: QDOT, STSF, navistar

Ref/DECA

Any advanced diagnostic & diagnostic caths

Auto or non-auto ID

Max of 10 poles

Pin box

Ex: Decanav, cs cath, auto ID Webster (& non-auto)

Quad A&B

Only webster

Diagnostic caths

Max 4 poles

Ex: Vizigo sheath, auto ID web HIS

20A & 20B Port

Connects advanced diagnostic & diagnostic

Max of 20 pole

20A supports TPI

Ex: Pentaray, Octaray, LAsso, Pin box, Decanav

Deca port

Only webster

Diagnostic

10 poles

Ex: Auto/non cs, auto/non his, auto/non quad