Fig 1.
A: Model geometry in which the volume was created by rotating a 2D model around the catheter axis. B: Detail of the scar included in the ventricular wall (case of fat deposition in the scar).
Fig 2.
Details of the modeled ventricular walls consisting of different tissues: Myocardium, fibrotic tissue and fat.
Table 1.
Electrical conductivities (S/m) of the tissues involved in the model pre- (σ0) and post-electroporation (σ1).
Fig 3.
Electric field distributions for the different cases considered (red color for >1000 V/cm and blue color for <490 V/cm) with 22 A current.
Lesion depth and surface width (in mm) induced by irreversible electroporation was computed with the 1000 V/cm isoline. In case D, the contour of the largest area of fat deposited in the scar is highlighted by a continuous thick white line.
Fig 4.
Lesion depths induced by irreversible electroporation (computed with the 1000 V/cm isoline) for different delivered currents and for the six considered cases.
The lines showing the “channel in scar” and “scar without fat deposition” are almost identical.
Table 2.
Lesion sizes computed by 1000 V/cm isoline (D: Depth; SW: Surface width) for different delivered current and considered cases of ventricular wall.
Fig 5.
A: Electric field distribution for heterogeneous model with fat deposition (22 A current). Detail of electric field (B) and electric field vector (C) around fat zones, showing ‘cold points’ and ‘hot points’ since electrical current tends to bypass fat due to its lower electrical conductivity.
Fig 6.
Mathematical justification of the boundary conditions of normal and tangential components (in red) of the electric field vector E at the interface between myocardium and fat.
As a result, the normal component of E in the fat is much greater than the normal component in myocardium, which implies that the electrical field vector is much greater in fat.
Fig 7.
Variation of voltage (A) and electric field (B) along the axis under the electrode, from the tissue surface (0 mm, inside the electrode) to a depth of 15 mm, for two ventricular walls: homogeneous myocardium (i.e. without scar), and scar with fat deposition. Note that the voltage drop (i.e. how fast it falls along the axis) is greater across the less conductive tissue (fat), which results in electric field values even higher than those in tissues closer to the ablation electrode (myocardium and fibrosis).