Abstract:
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Meshing the heart and measurement surfaces can be
time consuming, especially when dealing with complicated
geometries or cardiac motion. To overcome this, a
meshless method based on the method of fundamental
solutions (MFS) has been adapted to non-invasive
electrocardiographic imaging (ECGI). In the MFS,
potentials are expressed as a summation over a discrete set
of virtual point sources placed outside of the domain of
interest (named ‘pseudo-boundary’).
It is well-known that optimal placement of the pseudoboundary
can improve the efficacy of the MFS. Despite
this, there have been no attempts to optimize their
placement in the ECGI problem as far as we are aware.
In the standard MFS, the sources are placed in two
pseudo-boundaries constructed by inflating and deflating
the heart and torso surfaces with respect to the geometric
center of the heart. However, for some heart-torso
geometries, this geometric center is a poor reference. We
here show that adaptive placement of the pseudoboundaries
(depending on the distance between the torso
electrodes and the nearest heart locations) improves the
conditioning of the inverse problem, making it less
sensitive to the regularization process. |