Postnatal myocardium remodelling generates inhomogeneity in the architecture of the ventricular mass

Abstract

BackgroundThe 3D architecture of the ventricular mass is poorly known, although in vivo imaging techniques show the physiological inhomogeneity of ventricular walls mechanics. Polarized light imaging makes it possible to quantitatively analyse the myosin filament orientation.AimsIn this paper, we focus on the study the 3D architecture and regional isotropy of myocardial cells.MethodsTwenty normal human hearts, 10 from the perinatal period and 10 from the post-neonatal period were studied by polarized light microscopy. In each voxel of the ventricular mass (90 × 90 × 500 µm) the principal orientation segment was automatically and unambiguously extracted as well as a regional isotropy index (regional orientation tensor of the voxel neighbourhood).ResultsDuring the first months of postnatal age, the median regional isotropy values decreased in the ventricular mesh. This global decrease was not homogeneous across the ventricular walls. From the perinatal to the neonatal period, this decrease was more marked in the inner two-third of the lateral left ventricular wall and in the right part of the interventricular septum. There was a progressive post-neonatal appearance of a particularly inhomogeneous secondary arrangement of myocardial cells with alternation of thick low-RI and thin high-RI areas.ConclusionsThis study has shown a postnatal change in ventricular myocardial architecture, which became more inhomogeneous. The cell rearrangements responsible for the inhomogeneity in ventricular myocardial architecture are revealed by a variation of the regional isotropy index. These major changes are probably an adaptive consequence of the major haemodynamic changes occurring after birth during the neonatal period that generates major parietal stress variations and parietal remodelling.Electronic supplementary materialThe online version of this article (10.1007/s00276-017-1945-5) contains supplementary material, which is available to authorized users.

Polarized Light Imaging of the Myoarchitecture in Tetralogy of Fallot in the Perinatal Period

“…Our previous studies focused on the 3D myoarchitecture of perinatal and infant hearts with no detectable cardiac anomalies. Indeed, we showed that post-natal remodeling generates inhomogeneity in the 3D myoarchitecture of the ventricular mass and that this post-natal remodeling event is correlated with the post-natal appearance of the rotational mechanics of the left ventricle (22,23). The present study focuses on ToF-a frequent cardiac malformation -during the perinatal period.…”

Towards a multi-scale virtual heart model

“…Most studies are often limited by the anisotropy and/or low resolution of data as in Diffusion Tensor Imaging (DTI) [16] or Polarized Light Imaging (PLI) [17]. The recent work of our group [18]- [21] imaging human cardiac tissue with phase contrast SR-PCT, provides some quantitative knowledge about the 3D arrangement of the cellular and extra-cellular matrix at a micrometric isotropic spatial resolution.…”

“…In the future work, we will introduce statistics of the parameters, functional and dynamic information into our model in order to make it more realistic for virtual imaging. Moreover, the injection of experimental data as PLI [17] and SR-PCT [25], will increase the realistic rendering of the generated dataset.…”

The Memory of the Heart

“…The plasticity of myocardial tissue arrangement still present in this phase allows such adaptation. The ventricular myocardial architecture becomes more inhomogeneous, revealed by a variation of the regional isotropy index [46].…”