Mathematical models of ventricular cardiomyocyte orientation provide a simple description of histo-anatomical arrangements that are important for cardiac mechano-electric behaviour. They can be used to analyse interspecies differences, to explore dynamic remodelling such as during development or disease, and they are key for building realistic computational representations of the heart. This study investigates the suitability of regionally optimised models to represent accurately myocardial structure. Using DT-MRI scans as a reference, we calculate an optimised model by finding the parameters that minimise angular differences, both globally and regionally using a 16-segment topography. Results show angular differences between the optimized model and DT-MRI data of up to 15 degrees, with regional optimization providing a clear improvement in model accuracy (up to 52% error reduction). © 2011 Springer-Verlag Berlin Heidelberg.