Investigating the 3D Local Myocytes Arrangement in the Human LV Mid-Wall with the Transverse Angle

Myolaminar Layer Arrangement plays an essential role in cardiac biomechanics. In this preliminary study, we investigate the local 3D arrangement of the myocytes inside the sheets (layers) in three LV human heart transparietal samples imaged by X-ray phase contrast micro-tomography. We extract the large cleavage planes (CPs) of the extracellular matrix, manually select the middle wall region within each sample and compute the skeleton surface (chamfer distance and nonwitness-points selection) of the layers containing the myocytes. We compute the transverse angles of the myocytes in windows (32 × 32 × 32 voxels i.e. 112 × 112 × 112 μm3) centered on the 3D skeleton surface. Our results show that the myocytes are organized (i) in two populations in a LV samples close to the base with an angular distribution alternatively changing from one layer to the next and (ii) in a continuous angular evolution in samples located close to the apex. We find a mean angular difference between the two populations of about 8° in the two LV posterior samples and about 13° in the LV anterior sample. It is too early to statistically confirm that values as “universal” therefore we currently pursue our analysis of other available human LV samples to assess those first results.