In this work we introduce a new two-level preconditioner for the efficient solution of large-scale linear systems arising from the discretization of parametrized PDEs. The proposed preconditioner combines in a multiplicative way a reduced basis solver, whi ...

2018

A transmurally heterogeneous orthotropic activation model for ventricular contraction and its numerical validation

Alfio Quarteroni, Luca Dede', Simone Rossi, Luca Barbarotta

Models for cardiac mechanics require an activation mechanism properly representing the stress-strain relations in the contracting myocardium. In this paper, we propose a new activation model that accounts for the transmural heterogeneities observed in myoc ...

Wiley2018

Active contraction of cardiac cells: a reduced model for sarcomere dynamics with cooperative interactions

Alfio Quarteroni, Luca Dede', Francesco Regazzoni

We propose a reduced ODE model for the mechanical activation of cardiac myofilaments, which is based on explicit spatial representation of nearest-neighbour interactions. Our model is derived from the cooperative Markov Chain model of Washio et al. (Cell M ...

SPRINGER HEIDELBERG2018

A monolithic algorithm for the simulation of cardiac electromechanics in the human left ventricle

Alfio Quarteroni, Luca Dede', Antonello Gerbi

In this paper, we propose a monolithic algorithm for the numerical solution of the electromechanics model of the left ventricle in the human heart. Our coupled model integrates the monodomain equation with the Bueno-Orovio minimal model for electrophysiolo ...

2018

A high-order discontinuous Galerkin approximation to ordinary differential equations with applications to elastodynamics

Alfio Quarteroni, Niccolò Dal Santo

The aim of this work is to propose and analyse a new high-order discontinuous Galerkin finite element method for the time integration of a Cauchy problem for second-order ordinary differential equations. These equations typically arise after space semidisc ...

OXFORD UNIV PRESS2018

Improved hybrid/GPU algorithm for solving cardiac electrophysiology problems on Purkinje networks

Alfio Quarteroni, Christian Vergara, Toni Mikael Lassila

Cardiac Purkinje fibers provide an important pathway to the coordinated contraction of the heart. We present a numerical algorithm for the solution of electrophysiology problems across the Purkinje network that is efficient enough to be used in in silico s ...

Wiley2017

The cardiovascular system: Mathematical modelling, numerical algorithms and clinical applications

Alfio Quarteroni, Christian Vergara, Andrea Manzoni

Mathematical and numerical modelling of the cardiovascular system is a research topic that has attracted remarkable interest from the mathematical community because of its intrinsic mathematical difficulty and the increasing impact of cardiovascular diseas ...

Cambridge Univ Press2017

Complex blood flow patterns in an idealized left ventricle: A numerical study

Alfio Quarteroni, Anna Tagliabue

In this paper, we study the blood flow dynamics in a three-dimensional (3D) idealized left ventricle of the human heart whose deformation is driven by muscle contraction and relaxation in coordination with the action of the mitral and aortic valves. We pro ...

American Institute of Physics2017

Shear stress alterations in the celiac trunk of patients with a continuous-flow left ventricular assist device as shown by in-silico and in-vitro flow analyses

Alfio Quarteroni, Christian Vergara

BACKGROUND: The use of left ventricular assist devices (LVADs) to treat advanced cardiac heart failure is constantly increasing, although this device leads to high risk for gastrointestinal bleeding. METHODS: Using in-silico flow analysis, we quantified he ...

Elsevier Science Inc2017

A matrix DEIM technique for model reduction of nonlinear parametrized problems in cardiac mechanics

Alfio Quarteroni, Andrea Manzoni

When relying on Newton iterations to solve nonlinear problems in the context of Reduced Basis (RB) methods, the assembling of the RB arrays during the online stage depends on the dimension of the underlying high-fidelity approximation. This is more of an i ...

Elsevier Science Sa2017

A patient-specific aortic valve model based on moving resistive immersed implicit surfaces

Alfio Quarteroni, Elena Faggiano, Marco Fedele

In this paper, we propose a full computational framework to simulate the hemodynamics in the aorta including the valve. Closed and open valve surfaces, as well as the lumen aorta, are reconstructed directly from medical images using new ad hoc algorithms, ...

Springer Heidelberg2017

Numerical modeling of hemodynamics scenarios of patient-specific coronary artery bypass grafts

Alfio Quarteroni, Gianluigi Rozza, Andrea Manzoni, Elena Faggiano

A fast computational framework is devised to the study of several configurations of patient-specific coronary artery bypass grafts. This is especially useful to perform a sensitivity analysis of the hemodynamics for different flow conditions occurring in n ...

Springer Heidelberg2017

Fluid dynamics of an idealized left ventricle: the extended Nitsche's method for the treatment of heart valves as mixed time varying boundary conditions

Alfio Quarteroni, Anna Tagliabue

In this work, we study the blood flow dynamics in idealized left ventricles (LV) of the human heart modelled by the Navier-Stokes equations with mixed time varying boundary conditions. The latter are introduced for simulating the functioning of the aortic ...

Wiley2017

A computational fluid-structure interaction analysis of coronary Y-grafts

Alfio Quarteroni, Christian Vergara

Coronary artery disease is one of the leading causes of death worldwide. The stenotic coronary vessels are generally treated with coronary artery bypass grafts (CABGs), which can be either arterial (internal mammary artery, radial artery) or venous (saphen ...

Elsevier Sci Ltd2017

Large eddy simulations for blood dynamics in realistic stenotic carotids

Alfio Quarteroni, Christian Vergara

In this paper, we consider large eddy simulations (LES) for human stenotic carotids in presence of atheromasic plaque, a pathological condition where transitional effects to turbulence may occur, with relevant clinical implications such as plaque rupture. ...

Wiley2017

Isogeometric Analysis And Proper Orthogonal Decomposition For The Acoustic Wave Equation

Alfio Quarteroni, Shengfeng Zhu

Discretization methods such as finite differences or finite elements were usually employed to provide high fidelity solution approximations for reduced order modeling of parameterized partial differential equations. In this paper, a novel discretization te ...

Edp Sciences S A2017

Page 6 sur 13