The aim of this study is to investigate human left ventricular heart morphological changes in time among 17 healthy subjects. Preliminarily, 2 patients with volumetric overload due to aortic insufficiency were added to our analyses. We propose a special strategy to compare the shape, orientation and size of cardiac cycle’s morphological trajectories in time. We used 3D data obtained by Speckle Tracking Echocardiography in order to detect semi-automated and homologous landmarks clouds as proxies of left ventricular heart morphology. An extended Geometric Morphometrics toolkit in order to distinguish between intra- and inter-individual shape variations was used. Shape of trajectories with inter-individual variation were compared under the assumption that trajectories attributes, estimated at electrophysiologically homologous times are expressions of left ventricular heart function. We found that shape analysis as commonly applied in Geometric Morphometrics studies fails in identifying a proper morpho-space to compare the shape of morphological trajectories in time. To overcome this problem, we performed a special type of Riemannian Parallel Transport, called “linear shift”. Whereas the two patients with aortic insufficiency were not differentiated in the static shape analysis from the healthy subjects, they set apart significantly in the analyses of motion trajectory’s shape and orientation. We found that in healthy subjects, the variations due to inter-individual morphological differences were not related to shape and orientation of morphological trajectories. Principal Component Analysis showed that volumetric contraction, torsion and twist are differently distributed on different axes. Moreover, global shape change appeared to be more correlated with endocardial shape change than with the epicardial one. Finally, the total shape variation occurring among different subjects was significantly larger than that observable across properly defined morphological trajectories.

Model updating techniques are largely used in civil and mechanical engineering to obtain reliable FE models. The model parameters are iteratively adjusted until the model response matches the measured structural response within a given tolerance. The task is made difficult by the uncertainty that affects both the structural response and the model parameters. In this work, the uncertainty is taken into account by a proper formulation of the problem in the framework of interval analysis. Uncertainty is replaced by interval numbers, functions are replaced by their thin or thick natural extension and the inclusion theorem is exploited to find the problem solution. Sample applications are illustrated using a modal representation of the structure. A numerical example is used to discuss the potential of the proposed method. A case study is solved to demonstrate the advantages of the method with respect to conventional updating techniques.