We derive a constitutive law for the myocardium from the description of both the geometrical arrangement of
cardiomyocytes and their individual mechanical behaviour. We model a set of cardiomyocytes by a quasiperiodic discrete
lattice of elastic bars interacting by means of moments. We work in a large displacement framework and we use a discrete
homogenization technique. The macroscopic constitutive law is obtained through the resolution of a
nonlinear self-equilibrum system of the discrete lattice reference cell.