Fig. 3

a Computational domain \(\Omega _{} \subset {\mathbb {R}}^3\) in an idealized slab of ventricular myocardium, partitioned in three subdomains (\({\overline{\Omega }}_{} = {\overline{\Omega }}_{1} \cup {\overline{\Omega }}_{2} \cup {\overline{\Omega }}_{3}\)), where \(\Gamma _{12}\) and \(\Gamma _{23}\) denote the interfaces among the corresponding subdomains; (b) Representation of the orthonormal triplet for the myofiber orientations \({{\textbf{f}}_0}\) (fiber, in red), \({{\textbf{s}}_0}\) (sheet, in blu) and \({{\textbf{n}}_0}\) (sheet-normal, in green) in an idealized slab of ventricular tissue