the raw DT-MRI based anatomically and myofiber structure realistic computer simulation study of cardiac re-entry dynamics in the *in-silico* model of human foetal heart. [[[ The raw DT-MRI image data [@Pervolaraki-etal-2013] was segmented into the tissue/non-tissue pixels based on the MRI luminosity threshold, followed by the calculation of the fiber angles at each voxel from the diffusion-weighted DT-MRI images.]{} This very basic segmentation]{}]{} might be seen as a limitation of the study from the cardiac physiology point of view. However, the purpose of our study is not to provide results of immediate physiological or clinical relevance: for these we currently simply have not enough data. Rather, from the non-linear science point of view our rationale is to use the raw DT-MRI data “as is” as an example of an unaltered nature provided medium to study a re-entry dynamics. Although the DT-MRI yields three eigenvalues, the second and the third are often harder to distinguish, so we used only the primary eigenvector to define the local fibre orientations in the simulation study. The focus of the paper is to demonstrate the effect of a real mammalian heart anatomy and anisotropy on a re-entry dynamics. The available MRI data of a foetal 