heart provide an excellent oportunity for such study. The objectives for the use of foetal heart MRI data are: whether the anatomical settings of the although foetal but a real heart might support a positive filament tension re-entry, and what would it be the role of a real heart anisotropy in that case. So, here we demonstrate that the real heart anisotropy enhances re-entry self-termination.

We demonstrate that, in a 2D slice of the heart, the realistic fiber anisotropy might change the re-entry dynamics from pinned to anatomical re-entry.

In the full 3D DT-MRI based model, depending on the location of the re-entry initiation, the isotropic geometry of the heart might sustain perpetual re-entry even with a positive filament tension kinetics. While the same positive filament tension re-entry initiated at the same location of the foetal heart with the realistic fiber anisotropy self-terminates within seconds. Time of re-entry self-termination depends on the re-entry initial position. Anisotropy of the real heart speeds up re-entry self-termination, and in this sense has a rather anti-arrhythmogenic effect. [The geometry and anisotropy of the heart together ensure the fastest self-termination of cardiac re-entry]{}.

[The novel significance of our findings is that we demonstarte that the 