3D mapping
How 3D mapping systems work
Data is collected by dragging the catheter along the endocardial surface.
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A multipolar catheter is often utilised for optimal efficiency and accuracy
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A standard catheter can also be used but will collect less simultaneous data points
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Currently, in all the mapping systems, data acquisition is done automatically
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Location accuracy is evaluated at around
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0.5 mm for magnetic and
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0.6 mm for impedance based catheters.
High density mapping catheters
High density multipolar mapping catheters are ideal for 3D mapping as they cover a greater area, collecting an enormous amount of data in a faster amount of time.
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Common HD catheters include
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Carto: Optrell, Octaray, Pentaray
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Navx: HD grid, HD grid+
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Opal: orion
Carto / J&J Optrell
Carto / J&J Octaray
Carto / J&J Pentaray
Navx Abbott HD grid
Opal Boston Orion
Types of maps
Anatomical
Anatomy is reconstructed by catheter collection & can be merged with a pre-collected CT or MRI
Allows anatomical based ablation
AF ablation: sets of predefined linear lesions can be performed
Activation
Activation times at each recorded point of the map are compared with a reference time (IEGM or ECG)
colour coded from the beginning to the end of a predefined ‘‘window of interest’’
(from red to violet, through yellow, green and blue)
so revealing the circuit of re-entry or focal sources of activation.
Voltage
The amplitude of bipolar EGMs at each point are projected onto the anatomical shell, allowing visualisation of scars, borderline zones and healthy tissues, based on maximal voltage amplitude
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Carto example
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Normal tissues > 1.5 mV (violet)
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Inexcitable scars < 0.5 mV (red)
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Intermediary colours for border zones
Different mapping systems
Abbott Navx
Based on the measurement of electrical currents for 3D localisation of the catheters
(Impedance based)
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A low amplitude (1 mA) high-frequency (8.138 kHz) electrical current is alternatively delivered though six skin patches located on the patient’s chest in orthogonal planes, creating a voltage gradient along each direction (x, y and z)
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The catheter then measures at a high rate (100 times per second) the voltage of each electrical field, to determine its localisation in the 3D space
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any standard diagnostic and ablation catheter can be used to map
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A reference (intracardiac or external) is used for correction for patient movements or respiratory-induced motion
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A more recent version (Ensite X) includes additional magnetic navigation with dedicated catheters system, for more precise geometry.
-HD grid
-TactiFlex
Activation map of posterior LA focal ATc
Precision cart
Ensite X Cart
Johnson & Johnson Carto
magnetic fields are used for electroanatomical navigation and geometry reconstruction
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triangulation is performed by the system using three different ultralow magnetic fields making it possible to permanently measure the distance of the catheter with regard to each of three magnetic generators located beneath the operating table, thus allowing localisation of the catheter tip in space
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catheter tip orientation is displayed
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An external reference patch is positioned on the patient’s back for the detection of patient movements
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Dedicated manufactured catheters are needed with magnetic tip sensors
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Current versions include the possibility to visualise other non-dedicated catheters ( using impedance based navigation with six skin patches (like NavX)
cannot build geometry or tag local information on maps.
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ability to use ICE-based 3D reconstruction and integration of rotational angiography or fluoroscopy views.
Voltage map large area of scar anterior RA anterior
Activation map posterior LA top down activation for roof flutter
Boston Opal Cart
3 electromechanical fields
Boston Scientific Opal (previously Rhythmia) & Medtronic Affera
uses both magnetic & impedance-based techniques
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Dedicated magnetic-based catheters may be localised utilising a magnet under table
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other standard catheters are visualised through an impedance-based technique
Opal cannot be used without first creating a map using magnetic catheters.
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Medtronic Affera Voltage map of LA post PVI
Opal Cart
Biotronik Accutus (no longer exists)
AcQmap
Other mapping techniques
maps of fragmented/complex electrocardiograms during AF
-(the utility of which remains to be demonstrated)
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manual tagging of ventricular late potentials during SR or VP
-diastolic potentials
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Pace mapping is also available in 3D systems, depicting in colours on maps the various correlations between paced and spontaneous beats using automatic correlation algorithms
-sometimes used for mapping of ventricular arrhythmias
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contact force maps
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impedance maps
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isochrone maps
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ripple maps