Computational model of cardiac torsion

A novel finite-element model of ventricular torsion for the analysis of the twisting behaviour of the left human ventricle was developed, in order to investigate the influence of various biomechanical parameters on cardiac kinematics. The ventricle was simulated as a thick-walled ellipsoid composed of nine concentric layers. Arrays of reinforcement bars were embedded in each layer to mimic physiological myocardial anisotropy. The reinforcement bars were activated through an artificial combination of thermal and mechanical effects in order to obtain a contractile behaviour which is similar to that of myocardial fibres. The presence of an incompressible fluid inside the ventricular cavity was also simulated and the ventricle was combined with simple lumped-parameter hydraulic circuits reproducing preload and afterload. The model is able to reproduce a similar torsional behaviour to that of a physiological heart. Changes to a number of cardiac parameters, such as preload, afterload, fibre angle orientation and wall thickness, as well as the presence of small non-contractile areas, were introduced, in order to study the effects of these changes on cardiac torsion. The results of the simulations showed that there was sound correspondence between the model outcomes and available data from the literature. Results confirmed the importance of symmetric transmural patterns for fibre orientation. This model represents a fundamental step on the path towards unveiling the complexity of cardiac torsion, thus obtaining a practical and versatile tool to assist clinicians and researchers by providing them with easily-accessible, detailed data on cardiac kinematics for future diagnostic and surgical purposes.