Understanding the motion of the heart through the cardiac cycle can give useful insight for a range of different pathologies. In par- ticular, quantifying regional cardiac motion can help clinicians to better determine cardiac function by identifying regions of thickened, ischemic or infarcted tissue. In this work we propose a method for cardiac motion analysis to track the deformation of the left ventricle at a regional level. This method estimates the affine motion of distinct regions of the my- ocardium using a near incompressible non-rigid registration algorithm based on the Demon's optical flow approach. The global motion over the ventricle is computed by a smooth fusion of the deformation in each seg- ment using an anatomically aware poly-affine model for the heart. We apply the proposed method to a data-set of 10 volunteers. The results in- dicate that we are able to extract reasonably realistic deformation fields parametrised by a significantly reduced number of parameters compared to voxel-wise methods, which better enables for statistical analyses of the motion.